Chrome requires WebTouchPoint to store WebFloatPoint, instead of WebPoint.

content/renderer/input/input_handler_proxy.cc

 // Copyright 2013 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/renderer/input/input_handler_proxy.h"
 
 #include "base/debug/trace_event.h"
 #include "base/logging.h"
 #include "base/metrics/histogram.h"
 #include "content/renderer/input/input_handler_proxy_client.h"
 #include "third_party/WebKit/public/platform/Platform.h"
 #include "third_party/WebKit/public/web/WebInputEvent.h"
 #include "ui/events/latency_info.h"
 #include "ui/gfx/frame_time.h"
+#include "ui/gfx/geometry/point_conversions.h"
 
 using blink::WebFloatPoint;
 using blink::WebFloatSize;
 using blink::WebGestureEvent;
 using blink::WebInputEvent;
 using blink::WebMouseEvent;
 using blink::WebMouseWheelEvent;
 using blink::WebPoint;
 using blink::WebTouchEvent;
 using blink::WebTouchPoint;
@@ skipping 196 matching lines @@
       return DID_HANDLE;
     else if (!fling_may_be_active_on_main_thread_)
       return DROP_EVENT;
   } else if (event.type == WebInputEvent::TouchStart) {
     const WebTouchEvent& touch_event =
         *static_cast<const WebTouchEvent*>(&event);
     for (size_t i = 0; i < touch_event.touchesLength; ++i) {
       if (touch_event.touches[i].state != WebTouchPoint::StatePressed)
         continue;
       if (input_handler_->HaveTouchEventHandlersAt(
-              blink::WebPoint(touch_event.touches[i].position.x,
-                              touch_event.touches[i].position.y))) {
+              gfx::ToFlooredPoint(touch_event.touches[i].position))) {

[jdduke (slow), 2014/03/10 22:03:23]

What about changing InputHandler::HaveTouchEventHandlersAt() to take a
gfx::PointF? Or would that be a follow-up? Looking at LayerTreeHostImpl, it
should be able to operate on a gfx::PointF without any meaningful change other
than the method signature.

[tdresser, 2014/03/12 13:54:40]

I did that in patch set #4. It felt like it involved changing a bunch of code
with no clear benefit. Why do you feel it would be preferable? Just to reduce
the number of ToFlooredPoint calls?

         return DID_NOT_HANDLE;
       }
     }
     return DROP_EVENT;
   } else if (WebInputEvent::isKeyboardEventType(event.type)) {
     CancelCurrentFling(true);
   } else if (event.type == WebInputEvent::MouseMove) {
     const WebMouseEvent& mouse_event =
         *static_cast<const WebMouseEvent*>(&event);
     // TODO(tony): Ignore when mouse buttons are down?
@@ skipping 243 matching lines @@
   TRACE_EVENT2("renderer",
                "InputHandlerProxy::notifyCurrentFlingVelocity",
                "vx",
                velocity.width,
                "vy",
                velocity.height);
   input_handler_->NotifyCurrentFlingVelocity(ToClientScrollIncrement(velocity));
 }
 
 }  // namespace content