aura: Populate and use the newly added acceleration ratio fields in wheel-events.

content/browser/renderer_host/render_widget_host_impl.cc

 // 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_impl.h"
 
 #include <math.h>
 #include <utility>
 
 #include "base/auto_reset.h"
@@ skipping 96 matching lines @@
          touch.touches[0].state == WebKit::WebTouchPoint::StatePressed;
 }
 
 bool IsLastTouchEvent(const WebKit::WebTouchEvent& touch) {
   return touch.touchesLength == 1 &&
          touch.type == WebInputEvent::TouchEnd &&
          (touch.touches[0].state == WebKit::WebTouchPoint::StateReleased ||
           touch.touches[0].state == WebKit::WebTouchPoint::StateCancelled);
 }
 
+float GetUnacceleratedDelta(float accelerated_delta, float acceleration_ratio) {
+  if (acceleration_ratio == 0.f)
+    return accelerated_delta;
+  return accelerated_delta / acceleration_ratio;
+}
+
+float GetAccelerationRatio(float accelerated_delta, float unaccelerated_delta) {
+  if (unaccelerated_delta == 0.f || accelerated_delta == 0.f)
+    return 1.f;
+  return accelerated_delta / unaccelerated_delta;
+}
+
 }  // namespace
 
 
 // static
 void RenderWidgetHost::RemoveAllBackingStores() {
   BackingStoreManager::RemoveAllBackingStores();
 }
 
 // static
 size_t RenderWidgetHost::BackingStoreMemorySize() {
@@ skipping 832 matching lines @@
   // event, as for mouse moves) results in very slow scrolling on the Mac (on
   // which many, very small wheel events are sent).
   if (mouse_wheel_pending_) {
     if (coalesced_mouse_wheel_events_.empty() ||
         !ShouldCoalesceMouseWheelEvents(coalesced_mouse_wheel_events_.back(),
                                         wheel_event)) {
       coalesced_mouse_wheel_events_.push_back(wheel_event);
     } else {
       WebMouseWheelEvent* last_wheel_event =
           &coalesced_mouse_wheel_events_.back();
+      float unaccelerated_x =
+          GetUnacceleratedDelta(last_wheel_event->deltaX,
+                                last_wheel_event->accelerationRatioX) +
+          GetUnacceleratedDelta(wheel_event.deltaX,
+                                wheel_event.accelerationRatioX);
+      float unaccelerated_y =
+          GetUnacceleratedDelta(last_wheel_event->deltaY,
+                                last_wheel_event->accelerationRatioY) +
+          GetUnacceleratedDelta(wheel_event.deltaY,
+                                wheel_event.accelerationRatioY);
       last_wheel_event->deltaX += wheel_event.deltaX;
       last_wheel_event->deltaY += wheel_event.deltaY;
       last_wheel_event->wheelTicksX += wheel_event.wheelTicksX;
       last_wheel_event->wheelTicksY += wheel_event.wheelTicksY;
+      last_wheel_event->accelerationRatioX =
+          GetAccelerationRatio(last_wheel_event->deltaX, unaccelerated_x);
+      last_wheel_event->accelerationRatioY =
+          GetAccelerationRatio(last_wheel_event->deltaY, unaccelerated_y);
       DCHECK_GE(wheel_event.timeStampSeconds,
                 last_wheel_event->timeStampSeconds);
       last_wheel_event->timeStampSeconds = wheel_event.timeStampSeconds;
     }
     return;
   }
   mouse_wheel_pending_ = true;
   current_wheel_event_ = wheel_event;
 
   HISTOGRAM_COUNTS_100("MPArch.RWH_WheelQueueSize",
@@ skipping 1421 matching lines @@
     return;
 
   OnRenderAutoResized(new_size);
 }
 
 void RenderWidgetHostImpl::DetachDelegate() {
   delegate_ = NULL;
 }
 
 }  // namespace content