Move MessageLoop to base namespace.

android_webview/browser/aw_browser_main_parts.h

Index: android_webview/browser/aw_browser_main_parts.h
diff --git a/android_webview/browser/aw_browser_main_parts.h b/android_webview/browser/aw_browser_main_parts.h
index 669833b27ba4a545e82a8edfa46addf85f729fcb..b43e53b401479bae99125d024a716daddac61434 100644
--- a/android_webview/browser/aw_browser_main_parts.h
+++ b/android_webview/browser/aw_browser_main_parts.h
@@ -9,7 +9,9 @@
 #include "base/memory/scoped_ptr.h"
 #include "content/public/browser/browser_main_parts.h"
 
+namespace base {
 class MessageLoop;
+}
 
 namespace android_webview {
 
@@ -33,7 +35,7 @@ class AwBrowserMainParts : public content::BrowserMainParts {
 
  private:
   // Android specific UI MessageLoop.
-  scoped_ptr<MessageLoop> main_message_loop_;
+  scoped_ptr<base::MessageLoop> main_message_loop_;
 
   AwBrowserContext* browser_context_;  // weak
   AwDevToolsDelegate* devtools_delegate_;