DevTools: Avoid browser crash on undock after frontend self reloading.

chrome/browser/devtools/devtools_window.cc

 // Copyright (c) 2012 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.
 
 #include "chrome/browser/devtools/devtools_window.h"
 
 #include <algorithm>
 
 #include "base/command_line.h"
 #include "base/json/json_reader.h"
@@ skipping 1463 matching lines @@
   if (inspected_window)
     inspected_window->UpdateToolbar(NULL);
 }
 
 content::WebContents* DevToolsWindow::GetInspectedWebContents() {
   return inspected_contents_observer_ ?
       inspected_contents_observer_->web_contents() : NULL;
 }
 
 void DevToolsWindow::DocumentOnLoadCompletedInMainFrame() {
-  // Load is completed when both kIsDockedSet and kOnLoadFired happened.
-  // Here we set kOnLoadFired.
-  load_state_ = load_state_ == kIsDockedSet ? kLoadCompleted : kOnLoadFired;
+  // We could be in kLoadCompleted state already if frontend reloads itself.
+  if (load_state_ != kLoadCompleted) {
+    // Load is completed when both kIsDockedSet and kOnLoadFired happened.
+    // Here we set kOnLoadFired.
+    load_state_ = load_state_ == kIsDockedSet ? kLoadCompleted : kOnLoadFired;
+  }
   if (load_state_ == kLoadCompleted)
     LoadCompleted();
 }
 
 void DevToolsWindow::LoadCompleted() {
   Show(action_on_load_);
   action_on_load_ = DevToolsToggleAction::NoOp();
   UpdateTheme();
   AddDevToolsExtensionsToClient();
 }