[DevTools] Add explicit closing state in DevToolsWindow life time.

chrome/browser/devtools/devtools_window.h

 // 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.
 
 #ifndef CHROME_BROWSER_DEVTOOLS_DEVTOOLS_WINDOW_H_
 #define CHROME_BROWSER_DEVTOOLS_DEVTOOLS_WINDOW_H_
 
 #include "chrome/browser/devtools/devtools_contents_resizing_strategy.h"
 #include "chrome/browser/devtools/devtools_toggle_action.h"
 #include "chrome/browser/devtools/devtools_ui_bindings.h"
@@ skipping 168 matching lines @@
 
   // Notify devtools window that closing of |contents| was cancelled
   // by user.
   static void OnPageCloseCanceled(content::WebContents* contents);
 
  private:
   friend class DevToolsControllerTest;
   friend class DevToolsSanityTest;
   friend class BrowserWindowControllerTest;
 
-  // DevTools initialization typically follows this way:
+  // DevTools lifecycle typically follows this way:
   // - Toggle/Open: client call;
   // - Create;
   // - ScheduleShow: setup window to be functional, but not yet show;
   // - DocumentOnLoadCompletedInMainFrame: frontend loaded;
   // - SetIsDocked: frontend decided on docking state;
   // - OnLoadCompleted: ready to present frontend;
   // - Show: actually placing frontend WebContents to a Browser or docked place;
-  // - DoAction: perform action passed in Toggle/Open.
-  enum LoadState {
+  // - DoAction: perform action passed in Toggle/Open;
+  // - ...;
+  // - CloseWindow: initiates before unload handling;
+  // - CloseContents: destroys frontend;
+  // - DevToolsWindow is dead once it's main_web_contents dies.
+  enum LifeStage {
     kNotLoaded,
     kOnLoadFired, // Implies SetIsDocked was not yet called.
     kIsDockedSet, // Implies DocumentOnLoadCompleted was not yet called.
-    kLoadCompleted
+    kLoadCompleted,
+    kClosing
   };
 
   DevToolsWindow(Profile* profile,
                  const GURL& frontend_url,
                  content::RenderViewHost* inspected_rvh,
                  bool can_dock);
 
   static DevToolsWindow* Create(Profile* profile,
                                 const GURL& frontend_url,
                                 content::RenderViewHost* inspected_rvh,
@@ skipping 86 matching lines @@
 
   scoped_ptr<ObserverWithAccessor> inspected_contents_observer_;
 
   Profile* profile_;
   content::WebContents* main_web_contents_;
   content::WebContents* toolbox_web_contents_;
   DevToolsUIBindings* bindings_;
   Browser* browser_;
   bool is_docked_;
   const bool can_dock_;
-  LoadState load_state_;
+  LifeStage life_stage_;
   DevToolsToggleAction action_on_load_;
   bool ignore_set_is_docked_;
   DevToolsContentsResizingStrategy contents_resizing_strategy_;
   // True if we're in the process of handling a beforeunload event originating
   // from the inspected webcontents, see InterceptPageBeforeUnload for details.
   bool intercepted_page_beforeunload_;
   base::Closure load_completed_callback_;
 
   base::TimeTicks inspect_element_start_time_;
   scoped_ptr<DevToolsEventForwarder> event_forwarder_;
 
   friend class DevToolsEventForwarder;
   DISALLOW_COPY_AND_ASSIGN(DevToolsWindow);
 };
 
 #endif  // CHROME_BROWSER_DEVTOOLS_DEVTOOLS_WINDOW_H_