Mac: Add rails for scrolling.

content/browser/renderer_host/render_widget_host_view_mac.mm

 // 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.
 
 #include "content/browser/renderer_host/render_widget_host_view_mac.h"
 
 #import <objc/runtime.h>
 #include <OpenGL/gl.h>
 #include <QuartzCore/QuartzCore.h>
 
@@ skipping 17 matching lines @@
 #include "base/trace_event/trace_event.h"
 #import "content/browser/accessibility/browser_accessibility_cocoa.h"
 #include "content/browser/accessibility/browser_accessibility_manager_mac.h"
 #import "content/browser/cocoa/system_hotkey_helper_mac.h"
 #import "content/browser/cocoa/system_hotkey_map.h"
 #include "content/browser/compositor/resize_lock.h"
 #include "content/browser/frame_host/frame_tree.h"
 #include "content/browser/frame_host/frame_tree_node.h"
 #include "content/browser/frame_host/render_frame_host_impl.h"
 #include "content/browser/gpu/compositor_util.h"
+#include "content/browser/renderer_host/input/mouse_wheel_rails_filter_mac.h"
 #include "content/browser/renderer_host/render_view_host_impl.h"
 #include "content/browser/renderer_host/render_widget_helper.h"
 #import "content/browser/renderer_host/render_widget_host_view_mac_dictionary_helper.h"
 #import "content/browser/renderer_host/render_widget_host_view_mac_editcommand_helper.h"
 #import "content/browser/renderer_host/text_input_client_mac.h"
 #include "content/common/accessibility_messages.h"
 #include "content/common/edit_command.h"
 #include "content/common/gpu/gpu_messages.h"
 #include "content/common/input_messages.h"
 #include "content/common/view_messages.h"
@@ skipping 1685 matching lines @@
   self = [super initWithFrame:NSZeroRect];
   if (self) {
     self.acceptsTouchEvents = YES;
     editCommand_helper_.reset(new RenderWidgetHostViewMacEditCommandHelper);
     editCommand_helper_->AddEditingSelectorsToClass([self class]);
 
     renderWidgetHostView_.reset(r);
     canBeKeyView_ = YES;
     opaque_ = YES;
     focusedPluginIdentifier_ = -1;
+    mouseWheelFilter_.reset(new content::MouseWheelRailsFilterMac);
 
     // OpenGL support:
     if ([self respondsToSelector:
         @selector(setWantsBestResolutionOpenGLSurface:)]) {
       [self setWantsBestResolutionOpenGLSurface:YES];
     }
     [[NSNotificationCenter defaultCenter]
         addObserver:self
            selector:@selector(didChangeScreenParameters:)
                name:NSApplicationDidChangeScreenParametersNotification
@@ skipping 495 matching lines @@
   if ([event phase] != NSEventPhaseEnded &&
       [event phase] != NSEventPhaseCancelled) {
     return;
   }
 
   if (renderWidgetHostView_->render_widget_host_) {
     // History-swiping is not possible if the logic reaches this point.
     // Allow rubber-banding in both directions.
     bool canRubberbandLeft = true;
     bool canRubberbandRight = true;
-    const WebMouseWheelEvent webEvent = WebInputEventFactory::mouseWheelEvent(
+    WebMouseWheelEvent webEvent = WebInputEventFactory::mouseWheelEvent(
         event, self, canRubberbandLeft, canRubberbandRight);
+    webEvent.railsMode = mouseWheelFilter_->UpdateRailsMode(webEvent);
     renderWidgetHostView_->render_widget_host_->ForwardWheelEvent(webEvent);
   }
 
   if (endWheelMonitor_) {
     [NSEvent removeMonitor:endWheelMonitor_];
     endWheelMonitor_ = nil;
   }
 }
 
 - (void)beginGestureWithEvent:(NSEvent*)event {
@@ skipping 101 matching lines @@
       handler:^(NSEvent* blockEvent) {
           [self shortCircuitScrollWheelEvent:blockEvent];
           return blockEvent;
       }];
   }
 
   // This is responsible for content scrolling!
   if (renderWidgetHostView_->render_widget_host_) {
     BOOL canRubberbandLeft = [responderDelegate_ canRubberbandLeft:self];
     BOOL canRubberbandRight = [responderDelegate_ canRubberbandRight:self];
-    const WebMouseWheelEvent webEvent = WebInputEventFactory::mouseWheelEvent(
+    WebMouseWheelEvent webEvent = WebInputEventFactory::mouseWheelEvent(
         event, self, canRubberbandLeft, canRubberbandRight);
+    webEvent.railsMode = mouseWheelFilter_->UpdateRailsMode(webEvent);
     renderWidgetHostView_->render_widget_host_->ForwardWheelEvent(webEvent);
   }
 }
 
 // Called repeatedly during a pinch gesture, with incremental change values.
 - (void)magnifyWithEvent:(NSEvent*)event {
   if (!renderWidgetHostView_->render_widget_host_)
     return;
 
   // If, due to nesting of multiple gestures (e.g, from multiple touch
@@ skipping 1057 matching lines @@
 
 // "-webkit-app-region: drag | no-drag" is implemented on Mac by excluding
 // regions that are not draggable. (See ControlRegionView in
 // native_app_window_cocoa.mm). This requires the render host view to be
 // draggable by default.
 - (BOOL)mouseDownCanMoveWindow {
   return YES;
 }
 
 @end