[Sidebar V2] Make brave's panel header as SidePanel's header (#36472)

Sidebar v2 attaches a Brave-styled panel header at the SidePanel level instead of embedding it inside the content view. ## Changes - New BraveSidePanelHeader (view) + BraveSidePanelHeaderController (delegate) under brave/browser/ui/views/side_panel/. Visual spec (title, optional launch button + separator, close button, 60px height, Nala colors, Leo icons) mirrors V1's inline headers in BraveReadLaterSidePanelView/BraveBookmarksSidePanelView. - BraveSidePanelCoordinator::PopulateSidePanel attaches the header via upstream SidePanel::AddHeaderView only for entries ShouldShowBraveHeader allows (today: kReadingList, kBookmarks). - SidePanel chromium_src override now wraps upstream AddHeaderView / RemoveHeaderView so each call also re-runs Brave's UpdateBorder(). UpdateBorder() reserves a top inset equal to the header's preferred height when a header is attached, in both the rounded-border and no-border states. - brave_side_panel_header_controller is split into its own :side_panel_impl source_set (depending on :side_panel) to keep dep chains clean. ## Test plan - New SidebarBrowserTest.SidebarV2BraveHeaderTest test case - Manual: run with enable_sidebar_v2=true, open reading list and bookmarks — header should be visible
2026-05-19 13:13:51 +09:00
parent 8f148e3e0d
commit 0c1d146556
16 changed files with 434 additions and 33 deletions
@@ -3,5 +3,7 @@
 # License, v. 2.0. If a copy of the MPL was not distributed with this file,
 # You can obtain one at https://mozilla.org/MPL/2.0/.

-brave_browser_window_internal_deps =
-    [ "//brave/browser/ui/browser_window/internal" ]
+brave_browser_window_internal_deps = [
+  "//brave/browser/ui/browser_window/internal",
+  "//brave/browser/ui/sidebar/buildflags",
+]
@@ -56,6 +56,7 @@ if (toolkit_views) {
    "//brave/browser/ui/views/frame/vertical_tabs",
    "//brave/browser/ui/views/location_bar",
    "//brave/browser/ui/views/page_info",
+    "//brave/browser/ui/views/side_panel:side_panel_impl",
  ]

  if (enable_ai_chat) {
@@ -96,6 +96,7 @@
 #endif

 #if BUILDFLAG(ENABLE_SIDEBAR_V2)
+#include "brave/browser/ui/views/side_panel/brave_side_panel_header.h"
 #include "brave/browser/ui/views/side_panel/brave_side_panel_resize_area.h"
 #endif

@@ -2150,30 +2151,41 @@ IN_PROC_BROWSER_TEST_F(SidebarBrowserTest, SidebarV2ActiveItemStateSync) {
      [&]() { return !model()->active_index().has_value(); }));
 }

-// Verify that the upstream SidePanelHeader is never added when a sidebar panel
-// is opened in V2, so Brave can render its own header.
-IN_PROC_BROWSER_TEST_F(SidebarBrowserTest, SidebarV2NoUpstreamHeaderTest) {
+// Verify the Brave-styled side panel header is attached for reading list and
+// bookmarks and absent for other entries.
+IN_PROC_BROWSER_TEST_F(SidebarBrowserTest, SidebarV2BraveHeaderTest) {
  auto* panel_ui = browser()->GetFeatures().side_panel_ui();
  auto* browser_view = BrowserView::GetBrowserViewForBrowser(browser());
  auto* side_panel = browser_view->contents_height_side_panel();
  side_panel->DisableAnimationsForTesting();

-  panel_ui->Toggle();
-  ASSERT_TRUE(base::test::RunUntil([&]() { return side_panel->GetVisible(); }));
+  // Reading list: Brave header attached.
+  panel_ui->Show(SidePanelEntryId::kReadingList);
+  ASSERT_TRUE(base::test::RunUntil([&]() {
+    return panel_ui->IsSidePanelEntryShowing(
+        SidePanelEntry::Key(SidePanelEntryId::kReadingList));
+  }));
+  EXPECT_NE(nullptr, side_panel->GetHeaderView<BraveSidePanelHeader>())
+      << "BraveSidePanelHeader should be attached for the reading list panel";

-  EXPECT_EQ(nullptr, side_panel->GetHeaderView<views::View>())
-      << "Upstream SidePanelHeader should not be present after V2 panel open";
+  // Bookmarks: Brave header attached.
+  panel_ui->Show(SidePanelEntryId::kBookmarks);
+  ASSERT_TRUE(base::test::RunUntil([&]() {
+    return panel_ui->IsSidePanelEntryShowing(
+        SidePanelEntry::Key(SidePanelEntryId::kBookmarks));
+  }));
+  EXPECT_NE(nullptr, side_panel->GetHeaderView<BraveSidePanelHeader>())
+      << "BraveSidePanelHeader should be attached for the bookmarks panel";

-  // Also verify CustomizeChrome panel does not get an upstream header.
+  // CustomizeChrome: no Brave header (the previous one must be cleared when
+  // switching to an entry that doesn't request a Brave header).
  panel_ui->Show(SidePanelEntryId::kCustomizeChrome);
  ASSERT_TRUE(base::test::RunUntil([&]() {
    return panel_ui->IsSidePanelEntryShowing(
        SidePanelEntry::Key(SidePanelEntryId::kCustomizeChrome));
  }));
-
-  EXPECT_EQ(nullptr, side_panel->GetHeaderView<views::View>())
-      << "Upstream SidePanelHeader should not be present for CustomizeChrome "
-         "panel";
+  EXPECT_EQ(nullptr, side_panel->GetHeaderView<BraveSidePanelHeader>())
+      << "BraveSidePanelHeader should not be attached for CustomizeChrome";
 }

 // Verify that the resize area is positioned correctly for both border states.
@@ -23,8 +23,34 @@ source_set("side_panel") {

  if (enable_sidebar_v2) {
    sources += [
+      "brave_side_panel_header.cc",
+      "brave_side_panel_header.h",
+      "brave_side_panel_header_controller.h",
      "brave_side_panel_resize_area.cc",
      "brave_side_panel_resize_area.h",
    ]
  }
 }
+
+source_set("side_panel_impl") {
+  sources = []
+  deps = []
+
+  if (enable_sidebar_v2) {
+    sources += [ "brave_side_panel_header_controller.cc" ]
+
+    deps += [
+      ":side_panel",
+      "//base",
+      "//brave/app:brave_generated_resources_grit_grit",
+      "//brave/components/vector_icons",
+      "//chrome/app:generated_resources",
+      "//chrome/browser/ui/browser_window",
+      "//chrome/browser/ui/color:mixers",
+      "//chrome/browser/ui/side_panel:side_panel_views_dependent",
+      "//chrome/common",
+      "//ui/base",
+      "//ui/views",
+    ]
+  }
+}
@@ -10,6 +10,7 @@
 #include "base/check_op.h"
 #include "base/memory/raw_ref.h"
 #include "brave/browser/ui/color/brave_color_id.h"
+#include "brave/browser/ui/sidebar/features.h"
 #include "brave/components/vector_icons/vector_icons.h"
 #include "brave/grit/brave_generated_resources.h"
 #include "brave/ui/color/nala/nala_color_id.h"
@@ -141,6 +142,8 @@ END_METADATA

 BraveBookmarksSidePanelView::BraveBookmarksSidePanelView(
    SidePanelEntryScope& scope) {
+  CHECK(!base::FeatureList::IsEnabled(sidebar::features::kSidebarV2));
+
  CHECK_EQ(SidePanelEntryScope::ScopeType::kBrowser, scope.get_scope_type());
  SetLayoutManager(std::make_unique<views::FlexLayout>())
      ->SetOrientation(views::LayoutOrientation::kVertical);
@@ -9,6 +9,7 @@

 #include "base/functional/bind.h"
 #include "brave/browser/ui/color/brave_color_id.h"
+#include "brave/browser/ui/sidebar/features.h"
 #include "brave/components/vector_icons/vector_icons.h"
 #include "brave/grit/brave_generated_resources.h"
 #include "brave/ui/color/nala/nala_color_id.h"
@@ -112,6 +113,8 @@ BraveReadLaterSidePanelView::BraveReadLaterSidePanelView(
    TabStripModel* tab_strip_model,
    SidePanelEntryScope& scope,
    base::RepeatingClosure close_cb) {
+  CHECK(!base::FeatureList::IsEnabled(sidebar::features::kSidebarV2));
+
  SetLayoutManager(std::make_unique<views::FlexLayout>())
      ->SetOrientation(views::LayoutOrientation::kVertical);
  AddChildView(std::make_unique<ReadLaterSidePanelHeaderView>(scope));
@@ -26,6 +26,12 @@
 #include "chrome/browser/profiles/profile.h"
 #include "chrome/browser/ui/browser_window/public/browser_window_features.h"
 #include "chrome/browser/ui/side_panel/side_panel_entry.h"
+#include "chrome/browser/ui/views/side_panel/side_panel.h"
+
+#if BUILDFLAG(ENABLE_SIDEBAR_V2)
+#include "brave/browser/ui/views/side_panel/brave_side_panel_header.h"
+#include "brave/browser/ui/views/side_panel/brave_side_panel_header_controller.h"
+#endif

 namespace {

@@ -202,8 +208,27 @@ void BraveSidePanelCoordinator::PopulateSidePanel(
  SidePanelCoordinator::PopulateSidePanel(supress_animations, unique_key,
                                          std::move(open_trigger), entry,
                                          std::move(content_view));
+
+#if BUILDFLAG(ENABLE_SIDEBAR_V2)
+  if (ShouldShowBraveHeader(entry)) {
+    auto* side_panel = GetSidePanelFor(entry->type());
+    CHECK(side_panel);
+    side_panel->AddHeaderView(std::make_unique<BraveSidePanelHeader>(
+        std::make_unique<BraveSidePanelHeaderController>(
+            *browser_view_->browser(), entry)));
+  }
+#endif
 }

+#if BUILDFLAG(ENABLE_SIDEBAR_V2)
+bool BraveSidePanelCoordinator::ShouldShowBraveHeader(
+    SidePanelEntry* entry) const {
+  const SidePanelEntry::Id id = entry->key().id();
+  return id == SidePanelEntry::Id::kReadingList ||
+         id == SidePanelEntry::Id::kBookmarks;
+}
+#endif
+
 BraveBrowserView* BraveSidePanelCoordinator::GetBraveBrowserView() {
  return static_cast<BraveBrowserView*>(browser_view_);
 }
@@ -9,6 +9,7 @@
 #include <memory>
 #include <optional>

+#include "brave/browser/ui/sidebar/buildflags/buildflags.h"
 #include "chrome/browser/ui/views/side_panel/side_panel_coordinator.h"
 #include "chrome/browser/ui/views/side_panel/side_panel_helper.h"

@@ -52,6 +53,11 @@ class BraveSidePanelCoordinator : public SidePanelCoordinator {
  std::optional<SidePanelEntry::Key> GetLastActiveEntryKey() const;
  void UpdateToolbarButtonHighlight(bool side_panel_visible);
  BraveBrowserView* GetBraveBrowserView();
+
+#if BUILDFLAG(ENABLE_SIDEBAR_V2)
+  // Returns true when we want to show brave panel header view for |entry|.
+  bool ShouldShowBraveHeader(SidePanelEntry* entry) const;
+#endif
 };

 #endif  // BRAVE_BROWSER_UI_VIEWS_SIDE_PANEL_BRAVE_SIDE_PANEL_COORDINATOR_H_
@@ -0,0 +1,77 @@
+/* Copyright (c) 2026 The Brave Authors. All rights reserved.
+ * This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this file,
+ * You can obtain one at https://mozilla.org/MPL/2.0/. */
+
+#include "brave/browser/ui/views/side_panel/brave_side_panel_header.h"
+
+#include <utility>
+
+#include "base/check.h"
+#include "brave/ui/color/nala/nala_color_id.h"
+#include "ui/base/metadata/metadata_impl_macros.h"
+#include "ui/gfx/geometry/insets.h"
+#include "ui/views/background.h"
+#include "ui/views/controls/button/image_button.h"
+#include "ui/views/controls/label.h"
+#include "ui/views/controls/separator.h"
+#include "ui/views/layout/flex_layout.h"
+#include "ui/views/layout/flex_layout_types.h"
+#include "ui/views/layout/layout_types.h"
+#include "ui/views/view_class_properties.h"
+
+namespace {
+
+constexpr int kHeaderInteriorMargin = 16;
+constexpr int kHeaderButtonSize = 20;
+constexpr int kHeaderHeight = 60;
+constexpr int kSeparatorHorizontalSpacing = 12;
+
+}  // namespace
+
+BraveSidePanelHeader::BraveSidePanelHeader(std::unique_ptr<Delegate> delegate)
+    : delegate_(std::move(delegate)) {
+  CHECK(delegate_);
+
+  SetBackground(views::CreateSolidBackground(nala::kColorPageBackground));
+  SetLayoutManager(std::make_unique<views::FlexLayout>())
+      ->SetOrientation(views::LayoutOrientation::kHorizontal)
+      .SetInteriorMargin(gfx::Insets(kHeaderInteriorMargin))
+      .SetMainAxisAlignment(views::LayoutAlignment::kStart)
+      .SetCrossAxisAlignment(views::LayoutAlignment::kCenter);
+
+  AddChildView(delegate_->CreatePanelTitle());
+
+  AddChildView(std::make_unique<views::View>())
+      ->SetProperty(
+          views::kFlexBehaviorKey,
+          views::FlexSpecification(views::MinimumFlexSizeRule::kScaleToZero,
+                                   views::MaximumFlexSizeRule::kUnbounded)
+              .WithOrder(2));
+
+  if (auto launch_button = delegate_->CreateLaunchButton()) {
+    AddChildView(std::move(launch_button));
+    auto* separator = AddChildView(std::make_unique<views::Separator>());
+    separator->SetColorId(nala::kColorDividerSubtle);
+    separator->SetPreferredLength(kHeaderButtonSize);
+    separator->SetProperty(views::kMarginsKey,
+                           gfx::Insets::VH(0, kSeparatorHorizontalSpacing));
+  }
+
+  AddChildView(delegate_->CreateCloseButton());
+}
+
+BraveSidePanelHeader::~BraveSidePanelHeader() = default;
+
+void BraveSidePanelHeader::Layout(PassKey) {
+  LayoutSuperclass<views::View>(this);
+
+  // Need to set bounds as parent view(SidePanel) uses FillLayout.
+  const gfx::Rect contents_bounds = parent()->GetContentsBounds();
+  SetBoundsRect(gfx::Rect(contents_bounds.x(),
+                          contents_bounds.y() - kHeaderHeight,
+                          contents_bounds.width(), kHeaderHeight));
+}
+
+BEGIN_METADATA(BraveSidePanelHeader)
+END_METADATA
@@ -0,0 +1,48 @@
+/* Copyright (c) 2026 The Brave Authors. All rights reserved.
+ * This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this file,
+ * You can obtain one at https://mozilla.org/MPL/2.0/. */
+
+#ifndef BRAVE_BROWSER_UI_VIEWS_SIDE_PANEL_BRAVE_SIDE_PANEL_HEADER_H_
+#define BRAVE_BROWSER_UI_VIEWS_SIDE_PANEL_BRAVE_SIDE_PANEL_HEADER_H_
+
+#include <memory>
+
+#include "ui/base/metadata/metadata_header_macros.h"
+#include "ui/views/view.h"
+
+namespace views {
+class ImageButton;
+class Label;
+}  // namespace views
+
+// Header view shown on top of the side panel border in sidebar v2. The visual
+// spec mirrors the v1 inline headers in BraveReadLaterSidePanelView and
+// BraveBookmarksSidePanelView; per-entry pieces are produced by a Delegate.
+class BraveSidePanelHeader : public views::View {
+  METADATA_HEADER(BraveSidePanelHeader, views::View)
+
+ public:
+  class Delegate {
+   public:
+    virtual ~Delegate() = default;
+    virtual std::unique_ptr<views::Label> CreatePanelTitle() = 0;
+
+    // Return nullptr when the entry has no launch action (e.g. reading list).
+    virtual std::unique_ptr<views::ImageButton> CreateLaunchButton() = 0;
+    virtual std::unique_ptr<views::ImageButton> CreateCloseButton() = 0;
+  };
+
+  explicit BraveSidePanelHeader(std::unique_ptr<Delegate> delegate);
+  BraveSidePanelHeader(const BraveSidePanelHeader&) = delete;
+  BraveSidePanelHeader& operator=(const BraveSidePanelHeader&) = delete;
+  ~BraveSidePanelHeader() override;
+
+  // views::View:
+  void Layout(PassKey) override;
+
+ private:
+  std::unique_ptr<Delegate> delegate_;
+};
+
+#endif  // BRAVE_BROWSER_UI_VIEWS_SIDE_PANEL_BRAVE_SIDE_PANEL_HEADER_H_
@@ -0,0 +1,124 @@
+/* Copyright (c) 2026 The Brave Authors. All rights reserved.
+ * This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this file,
+ * You can obtain one at https://mozilla.org/MPL/2.0/. */
+
+#include "brave/browser/ui/views/side_panel/brave_side_panel_header_controller.h"
+
+#include <string>
+#include <utility>
+
+#include "base/functional/bind.h"
+#include "brave/browser/ui/color/brave_color_id.h"
+#include "brave/components/vector_icons/vector_icons.h"
+#include "brave/grit/brave_generated_resources.h"
+#include "chrome/browser/ui/browser_window/public/browser_window_features.h"
+#include "chrome/browser/ui/browser_window/public/browser_window_interface.h"
+#include "chrome/browser/ui/side_panel/side_panel_ui.h"
+#include "chrome/browser/ui/singleton_tabs.h"
+#include "chrome/common/webui_url_constants.h"
+#include "chrome/grit/generated_resources.h"
+#include "ui/base/l10n/l10n_util.h"
+#include "ui/base/models/image_model.h"
+#include "ui/gfx/font.h"
+#include "ui/gfx/font_list.h"
+#include "ui/views/controls/button/image_button.h"
+#include "ui/views/controls/label.h"
+
+namespace {
+
+constexpr int kHeaderTitleFontSize = 16;
+constexpr int kHeaderButtonSize = 20;
+
+std::unique_ptr<views::ImageButton> CreateHeaderImageButton(
+    views::Button::PressedCallback callback,
+    const gfx::VectorIcon& icon,
+    int tooltip_id) {
+  auto button = std::make_unique<views::ImageButton>(std::move(callback));
+  button->SetTooltipText(l10n_util::GetStringUTF16(tooltip_id));
+  button->SetImageModel(
+      views::Button::STATE_NORMAL,
+      ui::ImageModel::FromVectorIcon(icon, kColorSidebarPanelHeaderButton,
+                                     kHeaderButtonSize));
+  button->SetImageModel(
+      views::Button::STATE_HOVERED,
+      ui::ImageModel::FromVectorIcon(
+          icon, kColorSidebarPanelHeaderButtonHovered, kHeaderButtonSize));
+  return button;
+}
+
+// Per-panel header titles. Mirrors V1's hardcoded labels in
+// BraveReadLaterSidePanelView / BraveBookmarksSidePanelView; we deliberately
+// don't read from the entry's action item because that text differs from the
+// label V1 uses in the header.
+std::u16string GetEntryTitle(SidePanelEntry::Id id) {
+  int message_id = 0;
+  switch (id) {
+    case SidePanelEntry::Id::kReadingList:
+      message_id = IDS_SIDEBAR_READING_LIST_PANEL_HEADER_TITLE;
+      break;
+    case SidePanelEntry::Id::kBookmarks:
+      message_id = IDS_BOOKMARK_MANAGER_TITLE;
+      break;
+    default:
+      return std::u16string();
+  }
+  return l10n_util::GetStringUTF16(message_id);
+}
+
+}  // namespace
+
+BraveSidePanelHeaderController::BraveSidePanelHeaderController(
+    BrowserWindowInterface& browser_window,
+    SidePanelEntry* entry)
+    : browser_window_(browser_window), entry_(entry->GetWeakPtr()) {}
+
+BraveSidePanelHeaderController::~BraveSidePanelHeaderController() = default;
+
+std::unique_ptr<views::Label>
+BraveSidePanelHeaderController::CreatePanelTitle() {
+  CHECK(entry_);
+  auto label =
+      std::make_unique<views::Label>(GetEntryTitle(entry_->key().id()));
+  const int size_delta =
+      kHeaderTitleFontSize - views::Label::GetDefaultFontList().GetFontSize();
+  label->SetFontList(views::Label::GetDefaultFontList()
+                         .DeriveWithSizeDelta(size_delta)
+                         .DeriveWithWeight(gfx::Font::Weight::SEMIBOLD));
+  label->SetEnabledColor(kColorSidebarPanelHeaderTitle);
+  label->SetAutoColorReadabilityEnabled(false);
+  return label;
+}
+
+std::unique_ptr<views::ImageButton>
+BraveSidePanelHeaderController::CreateLaunchButton() {
+  CHECK(entry_);
+  if (entry_->key().id() == SidePanelEntry::Id::kBookmarks) {
+    return CreateHeaderImageButton(
+        base::BindRepeating(
+            &BraveSidePanelHeaderController::OnLaunchButtonPressed,
+            weak_factory_.GetWeakPtr(), GURL(chrome::kChromeUIBookmarksURL)),
+        kLeoLaunchIcon,
+        IDS_SIDEBAR_READING_LIST_PANEL_HEADER_BOOKMARKS_BUTTON_TOOLTIP);
+  }
+
+  return nullptr;
+}
+
+std::unique_ptr<views::ImageButton>
+BraveSidePanelHeaderController::CreateCloseButton() {
+  return CreateHeaderImageButton(
+      base::BindRepeating(&BraveSidePanelHeaderController::OnCloseButtonPressed,
+                          weak_factory_.GetWeakPtr()),
+      kLeoCloseIcon, IDS_SIDEBAR_PANEL_CLOSE_BUTTON_TOOLTIP);
+}
+
+void BraveSidePanelHeaderController::OnLaunchButtonPressed(const GURL& url) {
+  ShowSingletonTab(base::to_address(browser_window_), url);
+}
+
+void BraveSidePanelHeaderController::OnCloseButtonPressed() {
+  if (auto* side_panel_ui = browser_window_->GetFeatures().side_panel_ui()) {
+    side_panel_ui->Close(SidePanelEntry::PanelType::kContent);
+  }
+}
@@ -0,0 +1,48 @@
+/* Copyright (c) 2026 The Brave Authors. All rights reserved.
+ * This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this file,
+ * You can obtain one at https://mozilla.org/MPL/2.0/. */
+
+#ifndef BRAVE_BROWSER_UI_VIEWS_SIDE_PANEL_BRAVE_SIDE_PANEL_HEADER_CONTROLLER_H_
+#define BRAVE_BROWSER_UI_VIEWS_SIDE_PANEL_BRAVE_SIDE_PANEL_HEADER_CONTROLLER_H_
+
+#include <memory>
+
+#include "base/memory/raw_ref.h"
+#include "base/memory/weak_ptr.h"
+#include "brave/browser/ui/views/side_panel/brave_side_panel_header.h"
+#include "chrome/browser/ui/side_panel/side_panel_entry.h"
+#include "url/gurl.h"
+
+class BrowserWindowInterface;
+
+namespace views {
+class ImageButton;
+class Label;
+}  // namespace views
+
+class BraveSidePanelHeaderController : public BraveSidePanelHeader::Delegate {
+ public:
+  BraveSidePanelHeaderController(BrowserWindowInterface& browser_window,
+                                 SidePanelEntry* entry);
+  BraveSidePanelHeaderController(const BraveSidePanelHeaderController&) =
+      delete;
+  BraveSidePanelHeaderController& operator=(
+      const BraveSidePanelHeaderController&) = delete;
+  ~BraveSidePanelHeaderController() override;
+
+  // BraveSidePanelHeader::Delegate:
+  std::unique_ptr<views::Label> CreatePanelTitle() override;
+  std::unique_ptr<views::ImageButton> CreateLaunchButton() override;
+  std::unique_ptr<views::ImageButton> CreateCloseButton() override;
+
+ private:
+  void OnLaunchButtonPressed(const GURL& url);
+  void OnCloseButtonPressed();
+
+  const raw_ref<BrowserWindowInterface> browser_window_;
+  base::WeakPtr<SidePanelEntry> entry_;
+  base::WeakPtrFactory<BraveSidePanelHeaderController> weak_factory_{this};
+};
+
+#endif  // BRAVE_BROWSER_UI_VIEWS_SIDE_PANEL_BRAVE_SIDE_PANEL_HEADER_CONTROLLER_H_
@@ -8,6 +8,7 @@
 #include "brave/browser/ui/brave_browser_actions.h"
 #include "brave/browser/ui/brave_browser_command_controller.h"
 #include "brave/browser/ui/brave_browser_content_setting_bubble_model_delegate.h"
+#include "brave/browser/ui/sidebar/buildflags/buildflags.h"
 #include "brave/browser/ui/toolbar/brave_location_bar_model_delegate.h"
 #include "brave/browser/ui/views/side_panel/bookmarks/brave_bookmarks_side_panel_coordinator.h"
 #include "brave/browser/ui/views/side_panel/brave_side_panel_coordinator.h"
@@ -25,18 +26,24 @@
  BraveBrowserContentSettingBubbleModelDelegate
 #define BrowserWindowFeatures BrowserWindowFeatures_ChromiumImpl
 #define SidePanelCoordinator BraveSidePanelCoordinator
-#define BookmarksSidePanelCoordinator BraveBookmarksSidePanelCoordinator
 #define BrowserActions BraveBrowserActions
 #define BrowserCommandController BraveBrowserCommandController

+#if !BUILDFLAG(ENABLE_SIDEBAR_V2)
+#define BookmarksSidePanelCoordinator BraveBookmarksSidePanelCoordinator
+#endif
+
 #include <chrome/browser/ui/browser_window/internal/browser_window_features.cc>

+#if !BUILDFLAG(ENABLE_SIDEBAR_V2)
 #undef BookmarksSidePanelCoordinator
+#endif
+
+#undef BrowserCommandController
+#undef BrowserActions
 #undef SidePanelCoordinator
 #undef BrowserWindowFeatures
 #undef BrowserContentSettingBubbleModelDelegate
-#undef BrowserActions
-#undef BrowserCommandController

 const SidePanelUI* BrowserWindowFeatures_ChromiumImpl::side_panel_ui() const {
  return const_cast<BrowserWindowFeatures_ChromiumImpl*>(this)->side_panel_ui();
@@ -3,11 +3,16 @@
 // License, v. 2.0. If a copy of the MPL was not distributed with this file,
 // You can obtain one at https://mozilla.org/MPL/2.0/.

+#include "brave/browser/ui/sidebar/buildflags/buildflags.h"
 #include "brave/browser/ui/views/side_panel/brave_read_later_side_panel_view.h"
 #include "chrome/browser/ui/views/side_panel/reading_list/read_later_side_panel_web_view.h"

+#if !BUILDFLAG(ENABLE_SIDEBAR_V2)
 #define ReadLaterSidePanelWebView BraveReadLaterSidePanelView
+#endif

 #include <chrome/browser/ui/views/side_panel/reading_list/reading_list_side_panel_coordinator.cc>

+#if !BUILDFLAG(ENABLE_SIDEBAR_V2)
 #undef ReadLaterSidePanelWebView
+#endif
@@ -13,11 +13,10 @@
 // .cc pulls it in.
 #include "chrome/browser/ui/views/side_panel/side_panel.h"

-// Rename the upstream RemoveHeaderView implementation so we can provide
-// our own method. Upstream RemoveHeaderView() resets Border always but we
-// want to preserve the no-border state. As we don't set any header to all
-// panels, making it empty would not add any side-effect.
-#define RemoveHeaderView RemoveHeaderView_UnUsed
+// Rename the upstream Add/RemoveHeaderView implementation so we can provide
+// a thin wrapper that reapplies border state.
+#define AddHeaderView AddHeaderView_ChromiumImpl
+#define RemoveHeaderView RemoveHeaderView_ChromiumImpl

 // Rename the upstream Open/Close implementation so we can provide a thin
 // wrapper that reapplies border state after UpdateVisibility() runs.
@@ -31,6 +30,7 @@
 #undef Close
 #undef Open
 #undef RemoveHeaderView
+#undef AddHeaderView

 #endif  // BUILDFLAG(ENABLE_SIDEBAR_V2)

@@ -79,19 +79,32 @@ void SidePanel::UpdateBorder() {
    return;
  }

+  // When a Brave header is attached, reserve top inset for it so the header
+  // paints over the border strip without overlapping content.
+  const int header_top_inset =
+      header_view_ ? header_view_->GetPreferredSize().height() : 0;
+
  if (rounded_border_enabled_) {
    // Upstream GetBorderInsets() has a negative top to overlap the toolbar;
    // Brave doesn't need that overlap.
-    SetBorder(views::CreateEmptyBorder(GetBorderInsets().set_top(0)));
+    SetBorder(
+        views::CreateEmptyBorder(GetBorderInsets().set_top(header_top_inset)));
  } else {
-    SetBorder(nullptr);
+    SetBorder(
+        views::CreateEmptyBorder(gfx::Insets::TLBR(header_top_inset, 0, 0, 0)));
  }

  border_view_->SetVisible(rounded_border_enabled_);
 }

+void SidePanel::AddHeaderView(std::unique_ptr<views::View> view) {
+  AddHeaderView_ChromiumImpl(std::move(view));
+  UpdateBorder();
+}
+
 void SidePanel::RemoveHeaderView() {
-  // See above method overriding's comment why it's empty.
+  RemoveHeaderView_ChromiumImpl();
+  UpdateBorder();
 }

 #endif  // BUILDFLAG(ENABLE_SIDEBAR_V2)
@@ -22,14 +22,15 @@
 // Override Open/Close to apply our border style whenever open/close panel.
 // Override VisibilityChanged() is not sufficient as it's not called when
 // opening another panel while other panel is opened.
-#define GetContentParentView(...)                               \
-  GetContentParentView(__VA_ARGS__);                            \
-  void SetResizeArea(std::unique_ptr<views::View> resize_area); \
-  void SetRoundedBorderEnabled(bool enabled);                   \
-  void UpdateBorder();                                          \
-  void Open_ChromiumImpl(bool animated);                        \
-  void Close_ChromiumImpl(bool animated);                       \
-  void RemoveHeaderView_UnUsed()
+#define GetContentParentView(...)                                     \
+  GetContentParentView(__VA_ARGS__);                                  \
+  void SetResizeArea(std::unique_ptr<views::View> resize_area);       \
+  void SetRoundedBorderEnabled(bool enabled);                         \
+  void UpdateBorder();                                                \
+  void Open_ChromiumImpl(bool animated);                              \
+  void Close_ChromiumImpl(bool animated);                             \
+  void AddHeaderView_ChromiumImpl(std::unique_ptr<views::View> view); \
+  void RemoveHeaderView_ChromiumImpl()

 #define did_resize_    \
  did_resize_ = false; \