Add holdback feature parameter for measuring the impact of removing

debug strings

Bug: 399783247
Change-Id: I00de7344b3d1b8324dd2c1612daab56867f6e991
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/6332182
Reviewed-by: Kouhei Ueno <kouhei@chromium.org>
Commit-Queue: Jiacheng Guo <gjc@google.com>
Reviewed-by: Rakina Zata Amni <rakina@chromium.org>
Cr-Commit-Position: refs/heads/main@{#1430115}

content/browser/renderer_host/navigation_request.cc

@@ -4610,6 +4610,7 @@ void NavigationRequest::SelectFrameHostForOnResponseStarted(
       << "`render_frame_host_` should not be set before the "
          "`NavigationRequest` starts to select the RFH.";
   ScopedCrashKeys crash_keys(*this);
+  std::string rfh_selected_reason;
 
   // Select an appropriate renderer to commit the navigation.
   if (IsServedFromBackForwardCache()) {
@@ -4639,12 +4640,19 @@ void NavigationRequest::SelectFrameHostForOnResponseStarted(
                                  prerender_frame_tree_node_id_.value())
                              ->GetSafeRef();
   } else if (response_should_be_rendered_) {
+    std::string* reason_output =
+        base::FeatureList::IsEnabled(
+            features::kHoldbackDebugReasonStringRemoval)
+            ? &rfh_selected_reason
+            : nullptr;
+
     if (auto result =
             frame_tree_node_->render_manager()->GetFrameHostForNavigation(
                 this, &browsing_context_group_swap_,
                 ProcessAllocationContext::CreateForNavigationRequest(
                     ProcessAllocationNavigationStage::kAfterResponse,
-                    navigation_id_));
+                    navigation_id_),
+                reason_output);
         result.has_value()) {
       render_frame_host_ = result.value()->GetSafeRef();
     } else {
@@ -4865,6 +4873,16 @@ void NavigationRequest::SelectFrameHostForOnResponseStarted(
     return;
   }
 
+  // TODO(crbug.com/399783247): Remove
+  if (base::FeatureList::IsEnabled(
+          features::kHoldbackDebugReasonStringRemoval)) {
+    SCOPED_CRASH_KEY_STRING256(
+        "Bug1454273", "base_host_for_data_url",
+        common_params_->base_url_for_data_url.host_piece());
+    SCOPED_CRASH_KEY_STRING1024("Bug1454273", "rfh_selected_reason",
+                                rfh_selected_reason);
+  }
+
   if (HasRenderFrameHost() &&
       !CheckPermissionsPoliciesForFencedFrames(GetOriginToCommit().value())) {
     OnRequestFailedInternal(

content/browser/renderer_host/render_frame_host_manager.cc

@@ -1730,9 +1730,19 @@ RenderFrameHostManager::GetFrameHostForNavigation(
       render_frame_host_->IsNavigationSameSite(request->GetUrlInfo());
 
   IsSameSiteGetter is_same_site_getter(is_same_site);
+  std::string site_instance_reason;
+  std::string* reason_output =
+      base::FeatureList::IsEnabled(features::kHoldbackDebugReasonStringRemoval)
+          ? &site_instance_reason
+          : reason;
   scoped_refptr<SiteInstanceImpl> dest_site_instance =
       GetSiteInstanceForNavigationRequest(request, is_same_site_getter,
-                                          browsing_context_group_swap, reason);
+                                          browsing_context_group_swap,
+                                          reason_output);
+  if (base::FeatureList::IsEnabled(
+          features::kHoldbackDebugReasonStringRemoval)) {
+    reason->append(site_instance_reason);
+  }
 
   // A subframe should always be in the same BrowsingInstance as the parent
   // (see also https://crbug.com/1107269).

content/common/features.cc

@@ -65,6 +65,12 @@ BASE_FEATURE(kHidePastePopupOnGSB,
              base::FEATURE_ENABLED_BY_DEFAULT);
 #endif
 
+// Holdback the removal of debug reason strings in crrev.com/c/6312375
+// to measure the impact.
+BASE_FEATURE(kHoldbackDebugReasonStringRemoval,
+             "HoldbackDebugReasonStringRemoval",
+             base::FEATURE_DISABLED_BY_DEFAULT);
+
 // If Canvas2D Image Chromium is allowed, this feature controls whether it is
 // enabled.
 BASE_FEATURE(kCanvas2DImageChromium,

content/common/features.h

@@ -61,6 +61,7 @@ CONTENT_EXPORT BASE_DECLARE_FEATURE(kGroupNIKByJoiningOrigin);
 #if BUILDFLAG(IS_ANDROID)
 CONTENT_EXPORT BASE_DECLARE_FEATURE(kHidePastePopupOnGSB);
 #endif
+CONTENT_EXPORT BASE_DECLARE_FEATURE(kHoldbackDebugReasonStringRemoval);
 
 CONTENT_EXPORT BASE_DECLARE_FEATURE(kInMemoryCodeCache);
 CONTENT_EXPORT BASE_DECLARE_FEATURE(kInterestGroupUpdateIfOlderThan);