Set AllowOverlappingViews for history overlay

chrome/browser/ui/cocoa/browser_window_controller_private.mm

 // 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.
 
 #import "chrome/browser/ui/cocoa/browser_window_controller_private.h"
 
 #include <cmath>
 
 #include "base/command_line.h"
 #import "base/memory/scoped_nsobject.h"
@@ skipping 1012 matching lines @@
   if (chrome::IsInstantExtendedAPIEnabled())
     return YES;
 
   if (inPresentationMode)
     return YES;
 
   if (findBarCocoaController_ &&
       ![[findBarCocoaController_ findBarView] isHidden])
     return YES;
 
+  if (historyOverlayCount_)
+    return YES;
+
   return NO;
 }
 
 - (void)updateAllowOverlappingViews:(BOOL)inPresentationMode {
   WebContents* contents = browser_->tab_strip_model()->GetActiveWebContents();
   if (!contents)
     return;
   contents->GetView()->SetAllowOverlappingViews(
       [self shouldAllowOverlappingViews:inPresentationMode]);
 }
 
 - (void)updateInfoBarTipVisibility {
   // If the overlay is open or if there's no toolbar then hide the infobar tip.
   BOOL suppressInfoBarTip =
       [self currentInstantUIState] !=
       browser_window_controller::kInstantUINone || ![self hasToolbar];
   [infoBarContainerController_
       setShouldSuppressTopInfoBarTip:suppressInfoBarTip];
 }
 
 @end  // @implementation BrowserWindowController(Private)