speedreader: Add --speedreader-backend switch

Resolves https://github.com/brave/brave-browser/issues/14959

components/speedreader/speedreader_rewriter_service.cc

@@ -8,11 +8,12 @@
 #include <utility>
 
 #include "base/bind.h"
+#include "base/command_line.h"
 #include "base/files/file_util.h"
 #include "base/logging.h"
 #include "base/task/post_task.h"
-#include "brave/components/speedreader/rust/ffi/speedreader.h"
 #include "brave/components/speedreader/speedreader_component.h"
+#include "brave/components/speedreader/speedreader_switches.h"
 #include "components/grit/brave_components_resources.h"
 #include "ui/base/resource/resource_bundle.h"
 #include "url/gurl.h"
@@ -40,6 +41,16 @@ SpeedreaderRewriterService::SpeedreaderRewriterService(
     brave_component_updater::BraveComponent::Delegate* delegate)
     : component_(new speedreader::SpeedreaderComponent(delegate)),
       speedreader_(new speedreader::SpeedReader) {
+  const base::CommandLine& cmd_line = *base::CommandLine::ForCurrentProcess();
+  if (cmd_line.HasSwitch(speedreader::kSpeedreaderBackend)) {
+    // @pes mentioned we might want to experiment with several backends, so this
+    // will give us the most flexibility.
+    std::string backend = cmd_line.GetSwitchValueASCII(kSpeedreaderBackend);
+    if (backend == "heuristics") {
+      backend_ = RewriterType::RewriterHeuristics;
+    }
+  }
+
   // Load the built-in stylesheet as the default
   content_stylesheet_ =
       "<style id=\"brave_speedreader_style\">" +
@@ -84,12 +95,14 @@ void SpeedreaderRewriterService::OnStylesheetReady(const base::FilePath& path) {
 }
 
 bool SpeedreaderRewriterService::IsWhitelisted(const GURL& url) {
-  return speedreader_->IsReadableURL(url.spec());
+  return backend_ == RewriterType::RewriterStreaming
+             ? speedreader_->IsReadableURL(url.spec())
+             : true;
 }
 
 std::unique_ptr<Rewriter> SpeedreaderRewriterService::MakeRewriter(
     const GURL& url) {
-  return speedreader_->MakeRewriter(url.spec());
+  return speedreader_->MakeRewriter(url.spec(), backend_);
 }
 
 const std::string& SpeedreaderRewriterService::GetContentStylesheet() {

components/speedreader/speedreader_rewriter_service.h

@@ -12,6 +12,7 @@
 #include "base/memory/weak_ptr.h"
 #include "brave/components/brave_component_updater/browser/brave_component.h"
 #include "brave/components/brave_component_updater/browser/dat_file_util.h"
+#include "brave/components/speedreader/rust/ffi/speedreader.h"
 #include "brave/components/speedreader/speedreader_component.h"
 
 namespace base {
@@ -53,6 +54,10 @@ class SpeedreaderRewriterService : public SpeedreaderComponent::Observer {
   void OnLoadDATFileData(GetDATFileDataResult result);
   void OnLoadStylesheet(std::string stylesheet);
 
+  // This is currently the only backend reachable from browser code, so
+  // let's make it the default.
+  RewriterType backend_ = RewriterType::RewriterStreaming;
+
   std::string content_stylesheet_;
   std::unique_ptr<speedreader::SpeedreaderComponent> component_;
   std::unique_ptr<speedreader::SpeedReader> speedreader_;

components/speedreader/speedreader_switches.h

@@ -10,6 +10,7 @@ namespace speedreader {
 
 constexpr char kSpeedreaderWhitelist[] = "speedreader-whitelist";
 constexpr char kSpeedreaderWhitelistPath[] = "speedreader-whitelist-path";
+constexpr char kSpeedreaderBackend[] = "speedreader-backend";
 
 }  // namespace speedreader