Revert of Revert of DevTools: do not mute the protocol channel while reattaching.

Source/web/WebDevToolsAgentImpl.cpp

 /*
  * Copyright (C) 2010-2011 Google Inc. All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions are
  * met:
  *
  *     * Redistributions of source code must retain the above copyright
  * notice, this list of conditions and the following disclaimer.
  *     * Redistributions in binary form must reproduce the above
@@ skipping 222 matching lines @@
     ClientMessageLoopAdapter::inspectedViewClosed(m_webViewImpl);
     if (m_attached)
         Platform::current()->currentThread()->removeTaskObserver(this);
 }
 
 void WebDevToolsAgentImpl::attach(const WebString& hostId)
 {
     if (m_attached)
         return;
 
+    // Set the attached bit first so that sync notifications were delivered.
+    m_attached = true;
     inspectorController()->connectFrontend(hostId, this);
     Platform::current()->currentThread()->addTaskObserver(this);
-    m_attached = true;
 }
 
 void WebDevToolsAgentImpl::reattach(const WebString& hostId, const WebString& savedState)
 {
     if (m_attached)
         return;
 
+    // Set the attached bit first so that sync notifications were delivered.
+    m_attached = true;
     inspectorController()->reuseFrontend(hostId, this, savedState);
     Platform::current()->currentThread()->addTaskObserver(this);
-    m_attached = true;
 }
 
 void WebDevToolsAgentImpl::detach()
 {
     Platform::current()->currentThread()->removeTaskObserver(this);
 
     // Prevent controller from sending messages to the frontend.
     InspectorController* ic = inspectorController();
     ic->disconnectFrontend();
     m_attached = false;
@@ skipping 313 matching lines @@
     if (!InspectorBackendDispatcher::getCommandName(message, &commandName))
         return false;
     return commandName == InspectorBackendDispatcher::commandName(InspectorBackendDispatcher::kDebugger_pauseCmd)
         || commandName == InspectorBackendDispatcher::commandName(InspectorBackendDispatcher::kDebugger_setBreakpointCmd)
         || commandName == InspectorBackendDispatcher::commandName(InspectorBackendDispatcher::kDebugger_setBreakpointByUrlCmd)
         || commandName == InspectorBackendDispatcher::commandName(InspectorBackendDispatcher::kDebugger_removeBreakpointCmd)
         || commandName == InspectorBackendDispatcher::commandName(InspectorBackendDispatcher::kDebugger_setBreakpointsActiveCmd);
 }
 
 } // namespace blink