Move MessageLoop to base namespace.

content/renderer/devtools/devtools_agent_filter.h

Index: content/renderer/devtools/devtools_agent_filter.h
diff --git a/content/renderer/devtools/devtools_agent_filter.h b/content/renderer/devtools/devtools_agent_filter.h
index 9e4f8ae9221a5041125da81addf542a9ada4da8d..e7f78613807bcccb8f50885661dbf2a1e8acf3b9 100644
--- a/content/renderer/devtools/devtools_agent_filter.h
+++ b/content/renderer/devtools/devtools_agent_filter.h
@@ -9,9 +9,12 @@
 
 #include "ipc/ipc_channel_proxy.h"
 
-class MessageLoop;
 struct DevToolsMessageData;
 
+namespace base {
+class MessageLoop;
+}
+
 namespace content {
 
 // DevToolsAgentFilter is registered as an IPC filter in order to be able to
@@ -37,7 +40,7 @@ class DevToolsAgentFilter : public IPC::ChannelProxy::MessageFilter {
   void OnDispatchOnInspectorBackend(const std::string& message);
 
   bool message_handled_;
-  MessageLoop* render_thread_loop_;
+  base::MessageLoop* render_thread_loop_;
   int current_routing_id_;
 
   DISALLOW_COPY_AND_ASSIGN(DevToolsAgentFilter);