Make DevTools client survive 'refresh' of the inspectable tab.

chrome/renderer/devtools_agent.cc

 // Copyright (c) 2009 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.
 
 // DevToolsAgent belongs to the inspectable renderer and provides Glue's
 // agents with the communication capabilities. All messages from/to Glue's
 // agents infrastructure are flowing through this comminucation agent.
 //
 // DevToolsAgent is registered as an IPC filter in order to be able to
 // dispatch messages while on the IO thread. The reason for that is that while
@@ skipping 159 matching lines @@
 void DevToolsAgent::SendMessageToClient(const std::string& raw_msg) {
   Send(DevToolsClientMsg_RpcMessage(raw_msg));
 }
 
 void DevToolsAgent::OnRpcMessage(const std::string& raw_msg) {
   view_loop_->PostTask(FROM_HERE, NewRunnableMethod(
       this, &DevToolsAgent::DispatchRpcMessage, raw_msg));
 }
 
 void DevToolsAgent::OnInspectElement(int x, int y) {
-  WebDevToolsAgent* web_agent = view_->webview()->GetWebDevToolsAgent();
-  web_agent->InspectElement(x, y);
+  view_loop_->PostTask(FROM_HERE, NewRunnableMethod(
+      this, &DevToolsAgent::InspectElement, x, y));
 }
 
 void DevToolsAgent::DispatchRpcMessage(const std::string& raw_msg) {
-  WebDevToolsAgent* web_agent = view_->webview()->GetWebDevToolsAgent();
+  if (!view_)
+    return;
+  WebView* web_view = view_->webview();
+  if (!web_view)
+    return;
+  WebDevToolsAgent* web_agent = web_view->GetWebDevToolsAgent();
   web_agent->DispatchMessageFromClient(raw_msg);
 }
+
+void DevToolsAgent::InspectElement(int x, int y) {
+  if (!view_)
+    return;
+  WebView* web_view = view_->webview();
+  if (!web_view)
+    return;
+  WebDevToolsAgent* web_agent = web_view->GetWebDevToolsAgent();
+  web_agent->InspectElement(x, y);
+}