[cr147] //chorome/browser/domain_reliability has been componetized.

Chromium change:
https://source.chromium.org/chromium/chromium/src/+/78160d55

commit 78160d55e2c339974f49db81aa890db4d49d2dbe
Author: keybo <keybo@google.com>
Date:   Tue Mar 3 09:43:07 2026 -0800

    Modularize //chrome/browser/domain_reliability

    This change introduces the DomainReliabilityServiceDelegate to break the
    dependency of the domain_reliability component on g_browser_process and
    ChromeMetricsServiceAccessor. This allows
    //chrome/browser/domain_reliability to be extracted into its own build
    component.

    The DomainReliabilityServiceDelegate provides an interface for checking
    whether domain reliability is allowed by policy and if metrics reporting
    is enabled. This abstraction decouples the component from browser-level
    concepts.

    A production implementation, ChromeDomainReliabilityDelegate, is
    provided in //chrome/browser/net/profile_network_context_service.cc. A
    test implementation, TestDomainReliabilityServiceDelegate, is added for
    browser tests. This is a step towards reducing dependency cycles and
    improving the overall modularity of the codebase.

    Bug: 488383374

app/BUILD.gn

@@ -99,6 +99,7 @@ source_set("browser_tests") {
       "//chrome/app:command_ids",
       "//chrome/browser",
       "//chrome/browser/desktop_to_mobile_promos:utils",
+      "//chrome/browser/domain_reliability",
       "//chrome/browser/ui",
       "//chrome/common:non_code_constants",
       "//chrome/test",