PlzNavigate: Avoid creating WebUI for subframes.

content/browser/frame_host/render_frame_host_manager.cc

Index: content/browser/frame_host/render_frame_host_manager.cc
diff --git a/content/browser/frame_host/render_frame_host_manager.cc b/content/browser/frame_host/render_frame_host_manager.cc
index 5ae522b0a7b448c1cf8ab395d06544110703e08e..25b359fbb46b36018a13877769811832db7295ec 100644
--- a/content/browser/frame_host/render_frame_host_manager.cc
+++ b/content/browser/frame_host/render_frame_host_manager.cc
@@ -719,8 +719,6 @@ RenderFrameHostImpl* RenderFrameHostManager::GetFrameHostForNavigation(
   // The appropriate RenderFrameHost to commit the navigation.
   RenderFrameHostImpl* navigation_rfh = nullptr;
 
-  bool notify_webui_of_rf_creation = false;
-
   // Reuse the current RenderFrameHost if its SiteInstance matches the
   // navigation's.
   bool no_renderer_swap = current_site_instance == dest_site_instance.get();
@@ -749,6 +747,7 @@ RenderFrameHostImpl* RenderFrameHostManager::GetFrameHostForNavigation(
         request.dest_site_instance(), was_server_redirect);
   }
 
+  bool notify_webui_of_rf_creation = false;
   if (no_renderer_swap) {
     // GetFrameHostForNavigation will be called more than once during a
     // navigation (currently twice, on request and when it's about to commit in
@@ -759,8 +758,10 @@ RenderFrameHostImpl* RenderFrameHostManager::GetFrameHostForNavigation(
     if (speculative_render_frame_host_)
       DiscardUnusedFrame(UnsetSpeculativeRenderFrameHost());
 
-    UpdatePendingWebUIOnCurrentFrameHost(request.common_params().url,
-                                         request.bindings());
+    if (frame_tree_node_->IsMainFrame()) {
+      UpdatePendingWebUIOnCurrentFrameHost(request.common_params().url,
+                                           request.bindings());
+    }
 
     navigation_rfh = render_frame_host_.get();
 
@@ -785,13 +786,14 @@ RenderFrameHostImpl* RenderFrameHostManager::GetFrameHostForNavigation(
     }
     DCHECK(speculative_render_frame_host_);
 
-    bool changed_web_ui = speculative_render_frame_host_->UpdatePendingWebUI(
-        request.common_params().url, request.bindings());
-    speculative_render_frame_host_->CommitPendingWebUI();
-    DCHECK_EQ(GetNavigatingWebUI(), speculative_render_frame_host_->web_ui());
-    notify_webui_of_rf_creation =
-        changed_web_ui && speculative_render_frame_host_->web_ui();
-
+    if (frame_tree_node_->IsMainFrame()) {
+      bool changed_web_ui = speculative_render_frame_host_->UpdatePendingWebUI(
+          request.common_params().url, request.bindings());
+      speculative_render_frame_host_->CommitPendingWebUI();
+      DCHECK_EQ(GetNavigatingWebUI(), speculative_render_frame_host_->web_ui());
+      notify_webui_of_rf_creation =
+          changed_web_ui && speculative_render_frame_host_->web_ui();
+    }
     navigation_rfh = speculative_render_frame_host_.get();
 
     // Check if our current RFH is live.
@@ -835,7 +837,8 @@ RenderFrameHostImpl* RenderFrameHostManager::GetFrameHostForNavigation(
     if (!ReinitializeRenderFrame(navigation_rfh))
       return nullptr;
 
-    notify_webui_of_rf_creation = true;
+    if (frame_tree_node_->IsMainFrame())
+      notify_webui_of_rf_creation = true;
 
     if (navigation_rfh == render_frame_host_.get()) {
       // TODO(nasko): This is a very ugly hack. The Chrome extensions process