Fix mac_views_browser=1 compile.

chrome/browser/ui/views/omnibox/omnibox_popup_contents_view.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_UI_VIEWS_OMNIBOX_OMNIBOX_POPUP_CONTENTS_VIEW_H_
 #define CHROME_BROWSER_UI_VIEWS_OMNIBOX_OMNIBOX_POPUP_CONTENTS_VIEW_H_
 
 #include "base/memory/weak_ptr.h"
 #include "components/omnibox/browser/omnibox_popup_model.h"
 #include "components/omnibox/browser/omnibox_popup_view.h"
@@ skipping 139 matching lines @@
   // The popup sizes vertically using an animation when the popup is getting
   // shorter (not larger, that makes it look "slow").
   gfx::SlideAnimation size_animation_;
   gfx::Rect start_bounds_;
   gfx::Rect target_bounds_;
 
   int start_margin_;
   int end_margin_;
 
   // These pointers are owned by the resource bundle.
-  const gfx::ImageSkia* top_shadow_;
-  const gfx::ImageSkia* bottom_shadow_;
+  const gfx::ImageSkia* top_shadow_ = nullptr;
+  const gfx::ImageSkia* bottom_shadow_ = nullptr;
 
   // When the dropdown is not wide enough while displaying postfix suggestions,
   // we use the width of widest match contents to shift the suggestions so that
   // the widest suggestion just reaches the end edge.
   int max_match_contents_width_;
 
   DISALLOW_COPY_AND_ASSIGN(OmniboxPopupContentsView);
 };
 
 #endif  // CHROME_BROWSER_UI_VIEWS_OMNIBOX_OMNIBOX_POPUP_CONTENTS_VIEW_H_