content_shell: Use a ThreadRestrictions::ScopedAllowWait for layout tests on Android.

content/shell/webkit_test_controller.h

 // Copyright (c) 2012 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.
 
 #ifndef CONTENT_SHELL_WEBKIT_TEST_CONTROLLER_H_
 #define CONTENT_SHELL_WEBKIT_TEST_CONTROLLER_H_
 
 #include <ostream>
 #include <string>
 
 #include "base/cancelable_callback.h"
 #include "base/files/file_path.h"
 #include "base/synchronization/lock.h"
 #include "base/threading/non_thread_safe.h"
 #include "content/public/browser/gpu_data_manager_observer.h"
 #include "content/public/browser/notification_observer.h"
 #include "content/public/browser/notification_registrar.h"
 #include "content/public/browser/render_view_host_observer.h"
 #include "content/public/browser/web_contents_observer.h"
 #include "ui/gfx/size.h"
 #include "webkit/common/webpreferences.h"
 
+#if defined(OS_ANDROID)
+#include "base/threading/thread_restrictions.h"
+#endif
+
 class SkBitmap;
 
 namespace content {
 
 class Shell;
 
+#if defined(OS_ANDROID)
+// Android uses a nested message loop for running layout tests because the
+// default message loop, provided by the system, does not offer a blocking
+// Run() method. The loop itself, implemented as NestedMessagePumpAndroid,
+// uses a base::WaitableEvent allowing it to sleep until more events arrive.
+class ScopedAllowWaitForAndroidLayoutTests {
+ private:
+  base::ThreadRestrictions::ScopedAllowWait wait;
+};
+#endif
+
 class WebKitTestResultPrinter {
  public:
   WebKitTestResultPrinter(std::ostream* output, std::ostream* error);
   ~WebKitTestResultPrinter();
 
   void reset() {
     state_ = DURING_TEST;
   }
   bool output_finished() const { return state_ == AFTER_TEST; }
   void set_capture_text_only(bool capture_text_only) {
@@ skipping 143 matching lines @@
   gfx::Size initial_size_;
   GURL test_url_;
 
   // True if the WebPreferences of newly created RenderViewHost should be
   // overridden with prefs_.
   bool should_override_prefs_;
   WebPreferences prefs_;
 
   NotificationRegistrar registrar_;
 
+#if defined(OS_ANDROID)
+  // Because of the nested message pump implementation, Android needs to allow
+  // waiting on the UI thread while layout tests are being ran.
+  ScopedAllowWaitForAndroidLayoutTests reduced_restrictions_;
+#endif
+
   DISALLOW_COPY_AND_ASSIGN(WebKitTestController);
 };
 
 }  // namespace content
 
 #endif  // CONTENT_SHELL_WEBKIT_TEST_CONTROLLER_H_