Make pinch-zoom work for OOP PDF

extensions/browser/guest_view/guest_view_base.h

 // Copyright 2014 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 EXTENSIONS_BROWSER_GUEST_VIEW_GUEST_VIEW_BASE_H_
 #define EXTENSIONS_BROWSER_GUEST_VIEW_GUEST_VIEW_BASE_H_
 
 #include <queue>
 
 #include "base/memory/weak_ptr.h"
@@ skipping 300 matching lines @@
   void LoadingStateChanged(content::WebContents* source,
                            bool to_different_document) final;
   content::ColorChooser* OpenColorChooser(
       content::WebContents* web_contents,
       SkColor color,
       const std::vector<content::ColorSuggestion>& suggestions) override;
   void RunFileChooser(content::WebContents* web_contents,
                       const content::FileChooserParams& params) override;
   bool ShouldFocusPageAfterCrash() final;
   bool PreHandleGestureEvent(content::WebContents* source,
-                             const blink::WebGestureEvent& event) final;
+                             const blink::WebGestureEvent& event) override;
   void UpdatePreferredSize(content::WebContents* web_contents,
                            const gfx::Size& pref_size) final;
   void UpdateTargetURL(content::WebContents* source, const GURL& url) override;
 
  private:
   class OwnerLifetimeObserver;
 
   class OpenerLifetimeObserver;
 
   void DispatchEvent(Event* event, int instance_id);
@@ skipping 89 matching lines @@
   // This is used to ensure pending tasks will not fire after this object is
   // destroyed.
   base::WeakPtrFactory<GuestViewBase> weak_ptr_factory_;
 
   DISALLOW_COPY_AND_ASSIGN(GuestViewBase);
 };
 
 }  // namespace extensions
 
 #endif  // EXTENSIONS_BROWSER_GUEST_VIEW_GUEST_VIEW_BASE_H_