Don't re-use a zoom bubble unless it has the same web-contents.

chrome/browser/ui/views/location_bar/zoom_bubble_view_browsertest.cc

 // Copyright 2013 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/ui/views/location_bar/zoom_bubble_view.h"
 
 #include "chrome/browser/ui/browser_commands.h"
 #include "chrome/browser/ui/fullscreen/fullscreen_controller.h"
 #include "chrome/browser/ui/fullscreen/fullscreen_controller_test.h"
 #include "chrome/browser/ui/views/frame/browser_view.h"
@@ skipping 77 matching lines @@
   ZoomBubbleView::ShowBubble(web_contents, true);
   ASSERT_TRUE(ZoomBubbleView::IsShowing());
   const ZoomBubbleView* zoom_bubble = ZoomBubbleView::GetZoomBubbleForTest();
   EXPECT_FALSE(zoom_bubble->GetAnchorView());
 
   // An immersive reveal should hide the zoom bubble.
   scoped_ptr<ImmersiveRevealedLock> immersive_reveal_lock(
       immersive_controller->GetRevealedLock(
           ImmersiveModeController::ANIMATE_REVEAL_NO));
   ASSERT_TRUE(immersive_controller->IsRevealed());
-  EXPECT_TRUE(ZoomBubbleView::zoom_bubble_->GetWidget()->IsClosed());
+  EXPECT_EQ(NULL, ZoomBubbleView::zoom_bubble_);
 
   // The zoom bubble should be anchored when it is shown in immersive fullscreen
   // and the top-of-window views are revealed.
   ZoomBubbleView::ShowBubble(web_contents, true);
   ASSERT_TRUE(ZoomBubbleView::IsShowing());
   zoom_bubble = ZoomBubbleView::GetZoomBubbleForTest();
   EXPECT_TRUE(zoom_bubble->GetAnchorView());
 
   // The top-of-window views should not hide till the zoom bubble hides. (It
   // would be weird if the view to which the zoom bubble is anchored hid while
   // the zoom bubble was still visible.)
   immersive_reveal_lock.reset();
   EXPECT_TRUE(immersive_controller->IsRevealed());
   ZoomBubbleView::CloseBubble();
   // The zoom bubble is deleted on a task.
   content::RunAllPendingInMessageLoop();
   EXPECT_FALSE(immersive_controller->IsRevealed());
 
   // Exit fullscreen before ending the test for the sake of sanity.
   {
     scoped_ptr<FullscreenNotificationObserver> waiter(
         new FullscreenNotificationObserver());
     chrome::ToggleFullscreenMode(browser());
     waiter->Wait();
   }
 }
 #endif  // OS_CHROMEOS