InputHandlerProxy to inform blink scheduler of input events

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/auto_reset.h"
 #include "base/command_line.h"
 #include "base/debug/trace_event.h"
 #include "base/logging.h"
@@ skipping 177 matching lines @@
   InputHandlerProxy::EventDisposition disposition = HandleInputEvent(event);
   return disposition;
 }
 
 InputHandlerProxy::EventDisposition InputHandlerProxy::HandleInputEvent(
     const WebInputEvent& event) {
   DCHECK(input_handler_);
   TRACE_EVENT1("input", "InputHandlerProxy::HandleInputEvent",
                "type", WebInputEventTraits::GetName(event.type));
 
+  client_->DidReceiveInputEvent();

[jdduke (slow), 2014/09/11 16:29:35]

This method is called internally for synthetic wheel/fling gestures, is it OK
that the client is notified in such cases? Or do we only want it when we receive
an external event? Honestly, this method should be private, but I think
somewhere along the line somebody thought it convenient to keep public for
testing purposes.

[Sami, 2014/09/11 16:42:31]

I think we want to have it called for flings too, since they were still
initiated by the user and count as interacting with the device in my mind.

[alexclarke, 2014/09/11 16:45:00]

Yes I think we do want to treat synthetic events the same, since this should
make the user initiated animation smoother.

[jdduke (slow), 2014/09/11 16:49:11]

sgtm.

   if (FilterInputEventForFlingBoosting(event))
     return DID_HANDLE;
 
   if (event.type == WebInputEvent::MouseWheel) {
     const WebMouseWheelEvent& wheel_event =
         *static_cast<const WebMouseWheelEvent*>(&event);
     if (wheel_event.scrollByPage) {
       // TODO(jamesr): We don't properly handle scroll by page in the compositor
       // thread, so punt it to the main thread. http://crbug.com/236639
       return DID_NOT_HANDLE;
@@ skipping 600 matching lines @@
   // trigger a scroll, e.g., with a trivial time delta between fling updates.
   // Return true in this case to prevent early fling termination.
   if (std::abs(clipped_increment.width) < kScrollEpsilon &&
       std::abs(clipped_increment.height) < kScrollEpsilon)
     return true;
 
   return did_scroll;
 }
 
 }  // namespace content