Consolidate WebInputEvent coalescing logic

content/browser/renderer_host/input/immediate_input_router.cc

Index: content/browser/renderer_host/input/immediate_input_router.cc
diff --git a/content/browser/renderer_host/input/immediate_input_router.cc b/content/browser/renderer_host/input/immediate_input_router.cc
index b87cffc434dc27edb73fabb4de4e3a3ec57bd7ba..9b27f9d3b2bfc3f131720bc8f7b2dfd98c6c354a 100644
--- a/content/browser/renderer_host/input/immediate_input_router.cc
+++ b/content/browser/renderer_host/input/immediate_input_router.cc
@@ -36,27 +36,6 @@ using WebKit::WebMouseWheelEvent;
 namespace content {
 namespace {
 
-// Returns |true| if the two wheel events should be coalesced.
-bool ShouldCoalesceMouseWheelEvents(const WebMouseWheelEvent& last_event,
-                                    const WebMouseWheelEvent& new_event) {
-  return last_event.modifiers == new_event.modifiers &&
-         last_event.scrollByPage == new_event.scrollByPage &&
-         last_event.hasPreciseScrollingDeltas
-             == new_event.hasPreciseScrollingDeltas &&
-         last_event.phase == new_event.phase &&
-         last_event.momentumPhase == new_event.momentumPhase;
-}
-
-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;
-}
-
 const char* GetEventAckName(InputEventAckState ack_result) {
   switch(ack_result) {
     case INPUT_EVENT_ACK_STATE_UNKNOWN: return "UNKNOWN";
@@ -142,35 +121,8 @@ void ImmediateInputRouter::SendWheelEvent(
   // which many, very small wheel events are sent).
   if (mouse_wheel_pending_) {
     if (coalesced_mouse_wheel_events_.empty() ||
-        !ShouldCoalesceMouseWheelEvents(
-            coalesced_mouse_wheel_events_.back().event, wheel_event.event)) {
+        !coalesced_mouse_wheel_events_.back().TryCoalesceWith(wheel_event)) {
       coalesced_mouse_wheel_events_.push_back(wheel_event);
-    } else {
-      MouseWheelEventWithLatencyInfo* last_wheel_event =
-          &coalesced_mouse_wheel_events_.back();
-      float unaccelerated_x =
-          GetUnacceleratedDelta(last_wheel_event->event.deltaX,
-                                last_wheel_event->event.accelerationRatioX) +
-          GetUnacceleratedDelta(wheel_event.event.deltaX,
-                                wheel_event.event.accelerationRatioX);
-      float unaccelerated_y =
-          GetUnacceleratedDelta(last_wheel_event->event.deltaY,
-                                last_wheel_event->event.accelerationRatioY) +
-          GetUnacceleratedDelta(wheel_event.event.deltaY,
-                                wheel_event.event.accelerationRatioY);
-      last_wheel_event->event.deltaX += wheel_event.event.deltaX;
-      last_wheel_event->event.deltaY += wheel_event.event.deltaY;
-      last_wheel_event->event.wheelTicksX += wheel_event.event.wheelTicksX;
-      last_wheel_event->event.wheelTicksY += wheel_event.event.wheelTicksY;
-      last_wheel_event->event.accelerationRatioX =
-          GetAccelerationRatio(last_wheel_event->event.deltaX, unaccelerated_x);
-      last_wheel_event->event.accelerationRatioY =
-          GetAccelerationRatio(last_wheel_event->event.deltaY, unaccelerated_y);
-      DCHECK_GE(wheel_event.event.timeStampSeconds,
-                last_wheel_event->event.timeStampSeconds);
-      last_wheel_event->event.timeStampSeconds =
-          wheel_event.event.timeStampSeconds;
-      last_wheel_event->latency.MergeWith(wheel_event.latency);
     }
     return;
   }
@@ -230,16 +182,9 @@ void ImmediateInputRouter::SendMouseEventImmediately(
   // more WM_MOUSEMOVE events than we wish to send to the renderer.
   if (mouse_event.event.type == WebInputEvent::MouseMove) {
     if (mouse_move_pending_) {
-      if (!next_mouse_move_) {
+      if (!next_mouse_move_ ||
+          !next_mouse_move_->TryCoalesceWith(mouse_event)) {
         next_mouse_move_.reset(new MouseEventWithLatencyInfo(mouse_event));
-      } else {
-        // Accumulate movement deltas.
-        int x = next_mouse_move_->event.movementX;
-        int y = next_mouse_move_->event.movementY;
-        next_mouse_move_->event = mouse_event.event;
-        next_mouse_move_->event.movementX += x;
-        next_mouse_move_->event.movementY += y;
-        next_mouse_move_->latency.MergeWith(mouse_event.latency);
       }
       return;
     }