Mac: Add rails for scrolling.

content/browser/renderer_host/render_widget_host_view_mac.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_RENDERER_HOST_RENDER_WIDGET_HOST_VIEW_MAC_H_
 #define CONTENT_BROWSER_RENDERER_HOST_RENDER_WIDGET_HOST_VIEW_MAC_H_
 
 #import <Cocoa/Cocoa.h>
 #include <IOSurface/IOSurfaceAPI.h>
 #include <list>
@@ skipping 17 matching lines @@
 #import "content/public/browser/render_widget_host_view_mac_base.h"
 #include "ipc/ipc_sender.h"
 #include "third_party/WebKit/public/web/WebCompositionUnderline.h"
 #include "ui/accelerated_widget_mac/accelerated_widget_mac.h"
 #include "ui/accelerated_widget_mac/io_surface_layer.h"
 #include "ui/base/cocoa/base_view.h"
 #include "ui/base/cocoa/remote_layer_api.h"
 #include "ui/gfx/display_observer.h"
 
 namespace content {
+class MouseWheelRailsFilterMac;
+class RenderWidgetHostImpl;
 class RenderWidgetHostViewMac;
 class RenderWidgetHostViewMacEditCommandHelper;
 class WebContents;
 }
 
 namespace ui {
 class Compositor;
 class Layer;
 }
 
@@ skipping 116 matching lines @@
   // If true then escape key down events are suppressed until the first escape
   // key up event. (The up event is suppressed as well). This is used by the
   // flash fullscreen code to avoid sending a key up event without a matching
   // key down event.
   BOOL suppressNextEscapeKeyUp_;
 
   // The set of key codes from key down events that we haven't seen the matching
   // key up events yet.
   // Used for filtering out non-matching NSKeyUp events.
   std::set<unsigned short> keyDownCodes_;
+
+  // The filter used to guide touch events towards a horizontal or vertical
+  // orientation.
+  scoped_ptr<content::MouseWheelRailsFilterMac> mouseWheelFilter_;

[tdresser, 2015/03/19 13:03:41]

Why use a scoped_ptr here? It doesn't need to be nullable, does it?

[ccameron, 2015/03/19 19:33:14]

True -- done.

 }
 
 @property(nonatomic, readonly) NSRange selectedRange;
 @property(nonatomic, readonly) BOOL suppressNextEscapeKeyUp;
 
 - (void)setCanBeKeyView:(BOOL)can;
 - (void)setCloseOnDeactivate:(BOOL)b;
 - (void)setOpaque:(BOOL)opaque;
 - (void)setToolTipAtMousePoint:(NSString *)string;
 // True for always-on-top special windows (e.g. Balloons and Panels).
 - (BOOL)acceptsMouseEventsWhenInactive;
 // Cancel ongoing composition (abandon the marked text).
 - (void)cancelComposition;
 // Confirm ongoing composition.
 - (void)confirmComposition;
 // Enables or disables plugin IME.
 - (void)setPluginImeActive:(BOOL)active;
 // Updates the current plugin focus state.
 - (void)pluginFocusChanged:(BOOL)focused forPlugin:(int)pluginId;
 // Evaluates the event in the context of plugin IME, if plugin IME is enabled.
 // Returns YES if the event was handled.
 - (BOOL)postProcessEventForPluginIme:(NSEvent*)event;
 - (void)updateCursor:(NSCursor*)cursor;
 - (NSRect)firstViewRectForCharacterRange:(NSRange)theRange
                              actualRange:(NSRangePointer)actualRange;
 @end
 
 namespace content {
-class RenderWidgetHostImpl;
 
 ///////////////////////////////////////////////////////////////////////////////
 // RenderWidgetHostViewMac
 //
 //  An object representing the "View" of a rendered web page. This object is
 //  responsible for displaying the content of the web page, and integrating with
 //  the Cocoa view system. It is the implementation of the RenderWidgetHostView
 //  that the cross-platform RenderWidgetHost object uses
 //  to display the data.
 //
@@ skipping 361 matching lines @@
 
   // Factory used to safely scope delayed calls to ShutdownHost().
   base::WeakPtrFactory<RenderWidgetHostViewMac> weak_factory_;
 
   DISALLOW_COPY_AND_ASSIGN(RenderWidgetHostViewMac);
 };
 
 }  // namespace content
 
 #endif  // CONTENT_BROWSER_RENDERER_HOST_RENDER_WIDGET_HOST_VIEW_MAC_H_