Calling Shutdown() for Android content_browsertests. Removed webrtc test hack.

base/message_loop/message_pump_android.cc

Index: base/message_loop/message_pump_android.cc
diff --git a/base/message_loop/message_pump_android.cc b/base/message_loop/message_pump_android.cc
index ee8ff4d1a1aa99bd65690195fc10048660eca624..babd17b577ec0d45886bf88b81166837ddc46d0d 100644
--- a/base/message_loop/message_pump_android.cc
+++ b/base/message_loop/message_pump_android.cc
@@ -117,7 +117,7 @@ void MessagePumpForUI::Quit() {
     JNIEnv* env = base::android::AttachCurrentThread();
     DCHECK(env);
 
-    Java_SystemMessageHandler_removeScheduledWork(env,
+    Java_SystemMessageHandler_removeAllPendingMessages(env,
         system_message_handler_obj_.obj());
     system_message_handler_obj_.Reset();
   }