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

Wheel-scroll event deltas can have acceleration (e.g. when doing repeated
scrolls). But for overscroll, it makes more sense to use the unaccelerated
deltas.

BUG=175604

Review URL: https://codereview.chromium.org/12223110

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@182473 0039d316-1c4b-4281-b951-d872f2087c98

3 files changed, 36 insertions, 2 deletions

diff --git a/content/browser/renderer_host/overscroll_controller.cc b/content/browser/renderer_host/overscroll_controller.cc
index feb4247..dceefa4 100644
--- a/content/browser/renderer_host/overscroll_controller.cc
+++ b/content/browser/renderer_host/overscroll_controller.cc
@@ -171,8 +171,10 @@ void OverscrollController::ProcessEventForOverscroll(
     case WebKit::WebInputEvent::MouseWheel: {
       const WebKit::WebMouseWheelEvent& wheel =
           static_cast<const WebKit::WebMouseWheelEvent&>(event);
-      if (wheel.hasPreciseScrollingDeltas)
-        ProcessOverscroll(wheel.deltaX, wheel.deltaY);
+      if (wheel.hasPreciseScrollingDeltas) {
+        ProcessOverscroll(wheel.deltaX * wheel.accelerationRatioX,
+                          wheel.deltaY * wheel.accelerationRatioY);
+      }
       break;
     }
     case WebKit::WebInputEvent::GestureScrollUpdate: {
diff --git a/content/browser/renderer_host/render_widget_host_impl.cc b/content/browser/renderer_host/render_widget_host_impl.cc
index 5435407..ff96af2 100644
--- a/content/browser/renderer_host/render_widget_host_impl.cc
+++ b/content/browser/renderer_host/render_widget_host_impl.cc
@@ -114,6 +114,16 @@ bool IsLastTouchEvent(const WebKit::WebTouchEvent& touch) {
           touch.touches[0].state == WebKit::WebTouchPoint::StateCancelled);
 }
 
+float GetUnacceleratedDelta(float accelerated_delta, float acceleration_ratio) {
+  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 unaccelerated_delta / accelerated_delta;
+}
+
 }  // namespace
 
 
@@ -966,10 +976,24 @@ void RenderWidgetHostImpl::ForwardWheelEvent(
     } 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;
diff --git a/content/browser/renderer_host/web_input_event_aurax11.cc b/content/browser/renderer_host/web_input_event_aurax11.cc
index 122c345..8e4d193 100644
--- a/content/browser/renderer_host/web_input_event_aurax11.cc
+++ b/content/browser/renderer_host/web_input_event_aurax11.cc
@@ -145,9 +145,17 @@ WebKit::WebMouseWheelEvent MakeWebMouseWheelEventFromAuraEvent(
   webkit_event.timeStampSeconds = event->time_stamp().InSecondsF();
   webkit_event.hasPreciseScrollingDeltas = true;
   webkit_event.deltaX = event->x_offset();
+  if (event->x_offset_ordinal() != 0.f && event->x_offset() != 0.f) {
+    webkit_event.accelerationRatioX =
+        event->x_offset_ordinal() / event->x_offset();
+  }
   webkit_event.wheelTicksX = webkit_event.deltaX / kPixelsPerTick;
   webkit_event.deltaY = event->y_offset();
   webkit_event.wheelTicksY = webkit_event.deltaY / kPixelsPerTick;
+  if (event->y_offset_ordinal() != 0.f && event->y_offset() != 0.f) {
+    webkit_event.accelerationRatioY =
+        event->y_offset_ordinal() / event->y_offset();
+  }
 
   return webkit_event;
 }