Fix re-usage of stale cached WebPreferences in RenderViewHost.

content/shell/browser/layout_test/blink_test_controller.cc

 // Copyright 2013 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "content/shell/browser/layout_test/blink_test_controller.h"
 
 #include <stddef.h>
 
 #include <iostream>
 #include <set>
@@ skipping 744 matching lines @@
       render_view_host->GetRoutingID(), stitched_layout_dump));
 }
 
 void BlinkTestController::OnPrintMessage(const std::string& message) {
   printer_->AddMessageRaw(message);
 }
 
 void BlinkTestController::OnOverridePreferences(const WebPreferences& prefs) {
   should_override_prefs_ = true;
   prefs_ = prefs;
+
+  // Notifies the main RenderViewHost that Blink preferences changed so to avoid
+  // re-usage of cached preferences that are now stale.
+  RenderViewHost* main_render_view_host =
+      main_window_->web_contents()->GetRenderViewHost();
+  main_render_view_host->OnWebkitPreferencesChanged();
 }
 
 void BlinkTestController::OnClearDevToolsLocalStorage() {
   ShellBrowserContext* browser_context =
       ShellContentBrowserClient::Get()->browser_context();
   StoragePartition* storage_partition =
       BrowserContext::GetStoragePartition(browser_context, NULL);
   storage_partition->GetDOMStorageContext()->DeleteLocalStorage(
       content::LayoutTestDevToolsFrontend::GetDevToolsPathAsURL("", "")
           .GetOrigin());
@@ skipping 158 matching lines @@
   } else {
     printer_->AddErrorMessage(base::StringPrintf(
         "FAIL: Unexpected sendBluetoothManualChooserEvent() event name '%s'.",
         event_name.c_str()));
     return;
   }
   bluetooth_chooser_factory_->SendEvent(event, argument);
 }
 
 }  // namespace content