Enable pinch-zoom on the new login page.

extensions/browser/guest_view/web_view/web_view_guest.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_WEB_VIEW_WEB_VIEW_GUEST_H_
 #define EXTENSIONS_BROWSER_GUEST_VIEW_WEB_VIEW_WEB_VIEW_GUEST_H_
 
 #include <vector>
 
 #include "base/observer_list.h"
@@ skipping 61 matching lines @@
   void ShowContextMenu(
       int request_id,
       const WebViewGuestDelegate::MenuItemVector* items);
 
   // Sets the frame name of the guest.
   void SetName(const std::string& name);
 
   // Set the zoom factor.
   void SetZoom(double zoom_factor);
 
+  void SetAllowScaling(bool allow);
+
   // Sets the transparency of the guest.
   void SetAllowTransparency(bool allow);
 
   // Loads a data URL with a specified base URL and virtual URL.
   bool LoadDataWithBaseURL(const std::string& data_url,
                            const std::string& base_url,
                            const std::string& virtual_url,
                            std::string* error);
 
   // GuestViewBase implementation.
@@ skipping 27 matching lines @@
   void FindReply(content::WebContents* source,
                  int request_id,
                  int number_of_matches,
                  const gfx::Rect& selection_rect,
                  int active_match_ordinal,
                  bool final_update) override;
   bool HandleContextMenu(const content::ContextMenuParams& params) override;
   void HandleKeyboardEvent(
       content::WebContents* source,
       const content::NativeWebKeyboardEvent& event) override;
+  bool PreHandleGestureEvent(content::WebContents* source,
+                             const blink::WebGestureEvent& event) override;
   void RendererResponsive(content::WebContents* source) override;
   void RendererUnresponsive(content::WebContents* source) override;
   void RequestMediaAccessPermission(
       content::WebContents* source,
       const content::MediaStreamRequest& request,
       const content::MediaResponseCallback& callback) override;
   void RequestPointerLockPermission(
       bool user_gesture,
       bool last_unlocked_by_target,
       const base::Callback<void(bool)>& callback) override;
@@ skipping 216 matching lines @@
         name(name),
         changed(false) {}
   };
 
   using PendingWindowMap = std::map<WebViewGuest*, NewWindowInfo>;
   PendingWindowMap pending_new_windows_;
 
   // Stores the current zoom factor.
   double current_zoom_factor_;
 
+  // Determines if this guest accepts pinch-zoom gestures.
+  bool allow_scaling_;
+
   // This is used to ensure pending tasks will not fire after this object is
   // destroyed.
   base::WeakPtrFactory<WebViewGuest> weak_ptr_factory_;
 
   DISALLOW_COPY_AND_ASSIGN(WebViewGuest);
 };
 
 }  // namespace extensions
 
 #endif  // EXTENSIONS_BROWSER_GUEST_VIEW_WEB_VIEW_WEB_VIEW_GUEST_H_