Add touch scrolling modes experimental flags

content/browser/renderer_host/input/input_router_impl.cc

Index: content/browser/renderer_host/input/input_router_impl.cc
diff --git a/content/browser/renderer_host/input/input_router_impl.cc b/content/browser/renderer_host/input/input_router_impl.cc
index 3b68845ec3d2fe71ffea81f202a36ec10f4cb352..971d003edf0b8927f24a9493ede554530716cd63 100644
--- a/content/browser/renderer_host/input/input_router_impl.cc
+++ b/content/browser/renderer_host/input/input_router_impl.cc
@@ -115,6 +115,20 @@ const char* GetEventAckName(InputEventAckState ack_result) {
   return "";
 }
 
+TouchEventQueue::TouchScrollingMode GetTouchScrollingMode()
+{

[jdduke (slow), 2014/02/14 21:18:00]

Nit: Move brace up a line.  Also could you move this function to be by to the
other "configuration" functions above so I don't forget about it when
refactoring?

[tdresser, 2014/02/14 21:24:40]

Done.

+  std::string modeString = CommandLine::ForCurrentProcess()->
+      GetSwitchValueASCII(switches::kTouchScrollingMode);
+  if (modeString == switches::kTouchScrollingModeSyncTouchmove)
+    return TouchEventQueue::TOUCH_SCROLLING_MODE_SYNC_TOUCHMOVE;
+  if (modeString == switches::kTouchScrollingModeAbsorbTouchmove)
+    return TouchEventQueue::TOUCH_SCROLLING_MODE_ABSORB_TOUCHMOVE;
+  if (modeString != "" &&
+      modeString != switches::kTouchScrollingModeTouchcancel)
+    LOG(ERROR) << "Invalid --touch-scrolling-mode option: " << modeString;
+  return TouchEventQueue::TOUCH_SCROLLING_MODE_DEFAULT;
+}
+
 } // namespace
 
 InputRouterImpl::InputRouterImpl(IPC::Sender* sender,
@@ -136,8 +150,8 @@ InputRouterImpl::InputRouterImpl(IPC::Sender* sender,
   DCHECK(sender);
   DCHECK(client);
   DCHECK(ack_handler);
-  touch_event_queue_.reset(
-      new TouchEventQueue(this, GetTouchMoveSlopSuppressionLengthDips()));
+  touch_event_queue_.reset(new TouchEventQueue(
+      this, GetTouchScrollingMode(), GetTouchMoveSlopSuppressionLengthDips()));
   touch_ack_timeout_enabled_ =
       GetTouchAckTimeoutDelayMs(&touch_ack_timeout_delay_ms_);
   touch_event_queue_->SetAckTimeoutEnabled(touch_ack_timeout_enabled_,
@@ -328,6 +342,7 @@ void InputRouterImpl::OnTouchEventAck(const TouchEventWithLatencyInfo& event,
 void InputRouterImpl::OnGestureEventAck(
     const GestureEventWithLatencyInfo& event,
     InputEventAckState ack_result) {
+  touch_event_queue_->OnGestureEventAck(event, ack_result);
   ProcessAckForOverscroll(event.event, ack_result);
   ack_handler_->OnGestureEventAck(event, ack_result);
 }