mac: Only let two-finger-scrolling trigger history if web doesn't swallow gesture

content/browser/renderer_host/render_widget_host.h

 // Copyright (c) 2011 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_RENDERER_HOST_RENDER_WIDGET_HOST_H_
 #define CONTENT_BROWSER_RENDERER_HOST_RENDER_WIDGET_HOST_H_
 #pragma once
 
 #include <deque>
 #include <string>
@@ skipping 386 matching lines @@
   // not be sent to the renderer anymore. Otherwise, if the |event| would
   // 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);
 
   // Called when a keyboard event was not processed by the renderer. This is
   // overridden by RenderView to send upwards to its delegate.
   virtual void UnhandledKeyboardEvent(const NativeWebKeyboardEvent& event) {}
 
+  // Called when a mousewheel event was not processed by the renderer. This is
+  // overridden by RenderView to send upwards to its delegate.
+  virtual void UnhandledWheelEvent(const WebKit::WebMouseWheelEvent& event) {}
+
   // Notification that the user has made some kind of input that could
   // perform an action. The render view host overrides this to forward the
   // information to its delegate (see corresponding function in
   // RenderViewHostDelegate). The gestures that count are 1) any mouse down
   // event and 2) enter or space key presses.
   virtual void OnUserGesture() {}
 
   // Callbacks for notification when the renderer becomes unresponsive to user
   // input events, and subsequently responsive again. RenderViewHost overrides
   // these to tell its delegate to show the user a warning.
@@ skipping 86 matching lines @@
   // is the newly painted pixels by the renderer.
   void ScrollBackingStoreRect(int dx, int dy, const gfx::Rect& clip_rect,
                               const gfx::Size& view_size);
 
   // Called by OnMsgInputEventAck() to process a keyboard event ack message.
   void ProcessKeyboardEventAck(int type, bool processed);
 
   // Called by OnMsgInputEventAck() to process a wheel event ack message.
   // This could result in a task being posted to allow additional wheel
   // input messages to be coalesced.
-  void ProcessWheelAck();
+  void ProcessWheelAck(bool processed);
 
   // True if renderer accessibility is enabled. This should only be set when a
   // screenreader is detected as it can potentially slow down Chrome.
   bool renderer_accessible_;
 
   // The View associated with the RenderViewHost. The lifetime of this object
   // is associated with the lifetime of the Render process. If the Renderer
   // crashes, its View is destroyed and this pointer becomes NULL, even though
   // render_view_host_ lives on to load another URL (creating a new View while
   // doing so).
@@ skipping 55 matching lines @@
   // for a corresponding ViewHostMsg_HandleInputEvent_ACK message.
   bool mouse_move_pending_;
 
   // The next mouse move event to send (only non-null while mouse_move_pending_
   // is true).
   scoped_ptr<WebKit::WebMouseEvent> next_mouse_move_;
 
   // (Similar to |mouse_move_pending_|.) True if a mouse wheel event was sent
   // and we are waiting for a corresponding ack.
   bool mouse_wheel_pending_;
+  WebKit::WebMouseWheelEvent current_wheel_event_;
 
   typedef std::deque<WebKit::WebMouseWheelEvent> WheelEventQueue;
 
   // (Similar to |next_mouse_move_|.) The next mouse wheel events to send.
   // Unlike mouse moves, mouse wheel events received while one is pending are
   // coalesced (by accumulating deltas) if they match the previous event in
   // modifiers. On the Mac, in particular, mouse wheel events are received at a
   // high rate; not waiting for the ack results in jankiness, and using the same
   // mechanism as for mouse moves (just dropping old events when multiple ones
   // would be queued) results in very slow scrolling.
@@ skipping 78 matching lines @@
 
   std::vector<gfx::PluginWindowHandle> deferred_plugin_handles_;
 
   // The last scroll offset of the render widget.
   gfx::Point last_scroll_offset_;
 
   DISALLOW_COPY_AND_ASSIGN(RenderWidgetHost);
 };
 
 #endif  // CONTENT_BROWSER_RENDERER_HOST_RENDER_WIDGET_HOST_H_