Signal input flush when all flings have terminated

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 54bf892014c80b6884e624cdcdaac312c0817e46..654830ff79c0c0bf09b555388824afedd759b7fd 100644
--- a/content/browser/renderer_host/input/input_router_impl.cc
+++ b/content/browser/renderer_host/input/input_router_impl.cc
@@ -76,6 +76,7 @@ InputRouterImpl::InputRouterImpl(IPC::Sender* sender,
       current_view_flags_(0),
       current_ack_source_(ACK_SOURCE_NONE),
       flush_requested_(false),
+      active_fling_count_(0),
       touch_event_queue_(this, config.touch_config),
       gesture_event_queue_(this, this, config.gesture_config) {
   DCHECK(sender);
@@ -88,11 +89,6 @@ InputRouterImpl::~InputRouterImpl() {
   STLDeleteElements(&pending_select_messages_);
 }
 
-void InputRouterImpl::Flush() {
-  flush_requested_ = true;
-  SignalFlushedIfNecessary();
-}
-
 bool InputRouterImpl::SendInput(scoped_ptr<IPC::Message> message) {
   DCHECK(IPC_MESSAGE_ID_CLASS(message->type()) == InputMsgStart);
   switch (message->type()) {
@@ -244,6 +240,22 @@ void InputRouterImpl::OnViewUpdated(int view_flags) {
   UpdateTouchAckTimeoutEnabled();
 }
 
+void InputRouterImpl::RequestNotificationWhenFlushed() {
+  flush_requested_ = true;
+  SignalFlushedIfNecessary();
+}
+
+bool InputRouterImpl::HasPendingEvents() const {
+  return !touch_event_queue_.empty() ||
+         !gesture_event_queue_.empty() ||
+         !key_queue_.empty() ||
+         mouse_move_pending_ ||
+         mouse_wheel_pending_ ||
+         select_message_pending_ ||
+         move_caret_pending_ ||
+         active_fling_count_ > 0;
+}
+
 bool InputRouterImpl::OnMessageReceived(const IPC::Message& message) {
   bool handled = true;
   IPC_BEGIN_MESSAGE_MAP(InputRouterImpl, message)
@@ -257,6 +269,7 @@ bool InputRouterImpl::OnMessageReceived(const IPC::Message& message) {
                         OnHasTouchEventHandlers)
     IPC_MESSAGE_HANDLER(InputHostMsg_SetTouchAction,
                         OnSetTouchAction)
+    IPC_MESSAGE_HANDLER(InputHostMsg_DidStopFlinging, OnFlingingStopped)
     IPC_MESSAGE_UNHANDLED(handled = false)
   IPC_END_MESSAGE_MAP()
 
@@ -485,6 +498,13 @@ void InputRouterImpl::OnSetTouchAction(TouchAction touch_action) {
   UpdateTouchAckTimeoutEnabled();
 }
 
+void InputRouterImpl::OnFlingingStopped() {
+  DCHECK_GT(active_fling_count_, 0);
+  --active_fling_count_;
+  SignalFlushedIfNecessary();
+  client_->DidStopFlinging();
+}
+
 void InputRouterImpl::ProcessInputEventAck(
     WebInputEvent::Type event_type,
     InputEventAckState ack_result,
@@ -586,6 +606,11 @@ void InputRouterImpl::ProcessWheelAck(InputEventAckState ack_result,
 void InputRouterImpl::ProcessGestureAck(WebInputEvent::Type type,
                                         InputEventAckState ack_result,
                                         const ui::LatencyInfo& latency) {
+  if (type == blink::WebInputEvent::GestureFlingStart &&
+      ack_result == INPUT_EVENT_ACK_STATE_CONSUMED) {
+    ++active_fling_count_;
+  }

[Yufeng Shen (Slow to review), 2015/03/13 15:53:42]

I saw that gesture event queue also maintains a fling_in_progress bit. Can it
and active_fling_count_ somehow be merged into one ?

[jdduke (slow), 2015/03/13 16:08:04]

Probably, although the gesture queue fling in progress bit is a little
different, as it simply tracks whether we should discard a GestureFlingCancel at
the *end* of the queue. So if a fling is active and a GestureFlingCancel is
enqueued but not sent, it will think there's no fling in progress. It should
really be named "needs_fling_cancel_".

I'll see if I can merge the two, it might mean making the GEQ filter events when
they hit the head of the queue, rather than the tail. Will post back here.

+
   // |gesture_event_queue_| will forward to OnGestureEventAck when appropriate.
   gesture_event_queue_.ProcessGestureAck(ack_result, type, latency);
 }
@@ -626,14 +651,4 @@ void InputRouterImpl::SignalFlushedIfNecessary() {
   client_->DidFlush();
 }
 
-bool InputRouterImpl::HasPendingEvents() const {
-  return !touch_event_queue_.empty() ||
-         !gesture_event_queue_.empty() ||
-         !key_queue_.empty() ||
-         mouse_move_pending_ ||
-         mouse_wheel_pending_ ||
-         select_message_pending_ ||
-         move_caret_pending_;
-}
-
 }  // namespace content