[Mac] Fix crash when closing window if the devtools process was killed.

chrome/browser/ui/cocoa/browser_window_controller.mm

 // Copyright 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.
 
 #import "chrome/browser/ui/cocoa/browser_window_controller.h"
 
 #include <cmath>
 #include <numeric>
 
 #include "base/command_line.h"
@@ skipping 647 matching lines @@
   // We need to deactivate the controls (in the "WebView"). To do this, get the
   // selected WebContents's RenderWidgetHostView and tell it to deactivate.
   if (WebContents* contents =
           browser_->tab_strip_model()->GetActiveWebContents()) {
 
     DevToolsWindow* devtoolsWindow =
         DevToolsWindow::GetDockedInstanceForInspectedTab(contents);
     if (devtoolsWindow) {
       RenderWidgetHostView* devtoolsView =
           devtoolsWindow->web_contents()->GetRenderWidgetHostView();
-      if (devtoolsView->HasFocus()) {
+      if (devtoolsView && devtoolsView->HasFocus()) {
         devtoolsView->SetActive(false);
         return;
       }
     }
 
     if (RenderWidgetHostView* rwhv = contents->GetRenderWidgetHostView())
       rwhv->SetActive(false);
   }
 }
 
@@ skipping 1549 matching lines @@
 
 - (BOOL)supportsBookmarkBar {
   return [self supportsWindowFeature:Browser::FEATURE_BOOKMARKBAR];
 }
 
 - (BOOL)isTabbedWindow {
   return browser_->is_type_tabbed();
 }
 
 @end  // @implementation BrowserWindowController(WindowType)