Fix a crash in FullscreenExitBubbleController when the user clicks the "Exit full screen" button.

chrome/browser/ui/cocoa/browser_window_controller.mm

 // Copyright (c) 2011 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 1831 matching lines @@
   // Same as |x| above.
   CGFloat y = 0;
   if (NSMaxY(target) < NSMaxY(source))
     y = NSMaxY(source) - NSMaxY(target);
   else if (NSMinY(source) < NSMinY(target))
     y = NSMinY(source) - NSMinY(target);
 
   return NSMakeSize(x, y);
 }
 
+// (Private/TestingAPI)
+- (FullscreenExitBubbleController*)fullscreenExitBubbleController {
+  return fullscreenExitBubbleController_.get();
+}
+
 - (void)showInstant:(TabContents*)previewContents {
   [previewableContentsController_ showPreview:previewContents];
   [self updateBookmarkBarVisibilityWithAnimation:NO];
 }
 
 - (void)hideInstant {
   // TODO(rohitrao): Revisit whether or not this method should be called when
   // instant isn't showing.
   if (![previewableContentsController_ isShowingPreview])
     return;
@@ skipping 306 matching lines @@
 
 - (BOOL)supportsBookmarkBar {
   return [self supportsWindowFeature:Browser::FEATURE_BOOKMARKBAR];
 }
 
 - (BOOL)isTabbedWindow {
   return browser_->is_type_tabbed();
 }
 
 @end  // @implementation BrowserWindowController(WindowType)