Give blink a chance to consume ctrl+wheel events before zooming

content/browser/renderer_host/render_widget_host_delegate.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 CONTENT_BROWSER_RENDER_WIDGET_HOST_DELEGATE_H_
 #define CONTENT_BROWSER_RENDER_WIDGET_HOST_DELEGATE_H_
 
 #include "build/build_config.h"
 #include "content/common/content_export.h"
 #include "ui/gfx/native_widget_types.h"
@@ skipping 24 matching lines @@
   // be handled in HandleKeyboardEvent() method as a normal keyboard shortcut,
   // |*is_keyboard_shortcut| should be set to true.
   virtual bool PreHandleKeyboardEvent(const NativeWebKeyboardEvent& event,
                                       bool* is_keyboard_shortcut);
 
   // Callback to inform the browser that the renderer did not process the
   // specified events. This gives an opportunity to the browser to process the
   // event (used for keyboard shortcuts).
   virtual void HandleKeyboardEvent(const NativeWebKeyboardEvent& event) {}
 
-  // Callback to give the browser a chance to handle the specified mouse wheel
-  // event before sending it to the renderer.
-  // Returns true if the |event| was handled.
-  virtual bool PreHandleWheelEvent(const blink::WebMouseWheelEvent& event);
+  // Callback to inform the browser that the renderer did not process the
+  // specified mouse wheel event.  Returns true if the browser has handled
+  // the event itself.
+  virtual bool HandleWheelEvent(const blink::WebMouseWheelEvent& event);
 
   // Callback to give the browser a chance to handle the specified gesture
   // event before sending it to the renderer.
   // Returns true if the |event| was handled.
   virtual bool PreHandleGestureEvent(const blink::WebGestureEvent& event);
 
   // Notifies that screen rects were sent to renderer process.
   virtual void DidSendScreenRects(RenderWidgetHostImpl* rwh) {}
 
 #if defined(OS_WIN)
   // Returns the widget's parent's NativeViewAccessible.
   virtual gfx::NativeViewAccessible GetParentNativeViewAccessible();
 #endif
 
  protected:
   virtual ~RenderWidgetHostDelegate() {}
 };
 
 }  // namespace content
 
 #endif  // CONTENT_BROWSER_RENDER_WIDGET_HOST_DELEGATE_H_