Route touchmove existence notifications to the TouchEventQueue

content/browser/renderer_host/input/touch_event_queue.cc

Index: content/browser/renderer_host/input/touch_event_queue.cc
diff --git a/content/browser/renderer_host/input/touch_event_queue.cc b/content/browser/renderer_host/input/touch_event_queue.cc
index 35b1657048ba5635cf1ffbba8c353f8687b94359..0ef95f9f391543ea239359ea7d84d8535189f4c0 100644
--- a/content/browser/renderer_host/input/touch_event_queue.cc
+++ b/content/browser/renderer_host/input/touch_event_queue.cc
@@ -29,6 +29,21 @@ const double kAsyncTouchMoveIntervalSec = .2;
 // |causesScrollingIfUncanceled| bit.
 const double kMaxConceivablePlatformSlopRegionLengthDipsSquared = 60. * 60.;
 
+// These values should be synchronized with those in histograms.xml.
+enum TouchSequenceHandlerType {
+  HAS_HANDLER,
+  HAS_HANDLER_BUT_NO_MOVE_HANDLERS_FOR_PAGE,
+  NO_HANDLERS_FOR_PAGE,
+  NO_HANDLER_FOR_SEQUENCE,
+  UNKNOWN_BECAUSE_TIMEOUT,
+  TOUCH_SEQUENCE_HANDLER_TYPE_COUNT
+};
+
+void LogSequenceHandlerType(TouchSequenceHandlerType type) {
+  UMA_HISTOGRAM_ENUMERATION("Event.TouchSequence.HandlerType", type,
+                            TOUCH_SEQUENCE_HANDLER_TYPE_COUNT);
+}
+
 TouchEventWithLatencyInfo ObtainCancelEventForTouchEvent(
     const TouchEventWithLatencyInfo& event_to_cancel) {
   TouchEventWithLatencyInfo event = event_to_cancel;
@@ -131,8 +146,6 @@ class TouchEventQueue::TouchTimeoutHandler {
           touch_queue_->SendTouchEventImmediately(&cancel_event);
         } else {
           SetPendingAckState(PENDING_ACK_NONE);
-          touch_queue_->UpdateTouchConsumerStates(timeout_event_.event,
-                                                  ack_result);
         }
         return true;
       case PENDING_ACK_CANCEL_EVENT:
@@ -181,6 +194,10 @@ class TouchEventQueue::TouchTimeoutHandler {
 
   bool IsTimeoutTimerRunning() const { return timeout_monitor_.IsRunning(); }
 
+  bool HasTimeoutEvent() const {
+    return pending_ack_state_ != PENDING_ACK_NONE;
+  }
+
   bool IsEnabled() const {
     return enabled_ && !GetTimeoutDelay().is_zero();
   }
@@ -254,10 +271,6 @@ class TouchEventQueue::TouchTimeoutHandler {
     return use_mobile_timeout_ ? mobile_timeout_delay_ : desktop_timeout_delay_;
   }
 
-  bool HasTimeoutEvent() const {
-    return pending_ack_state_ != PENDING_ACK_NONE;
-  }
-
 
   TouchEventQueue* touch_queue_;
 
@@ -433,6 +446,7 @@ TouchEventQueue::TouchEventQueue(TouchEventQueueClient* client,
       dispatching_touch_ack_(false),
       dispatching_touch_(false),
       has_handlers_(true),
+      has_move_handlers_(true),
       has_handler_for_current_sequence_(false),
       drop_remaining_touches_in_sequence_(false),
       touchmove_slop_suppressor_(new TouchMoveSlopSuppressor),
@@ -462,10 +476,12 @@ void TouchEventQueue::QueueEvent(const TouchEventWithLatencyInfo& event) {
     // yields identical results, but this avoids unnecessary allocations.
     PreFilterResult filter_result = FilterBeforeForwarding(event.event);
     if (filter_result != FORWARD_TO_RENDERER) {
-      client_->OnTouchEventAck(event,
-                               filter_result == ACK_WITH_NO_CONSUMER_EXISTS
-                                   ? INPUT_EVENT_ACK_STATE_NO_CONSUMER_EXISTS
-                                   : INPUT_EVENT_ACK_STATE_NOT_CONSUMED);
+      InputEventAckState ack_result =
+          filter_result == ACK_WITH_NO_CONSUMER_EXISTS
+              ? INPUT_EVENT_ACK_STATE_NO_CONSUMER_EXISTS
+              : INPUT_EVENT_ACK_STATE_NOT_CONSUMED;
+      UpdateTouchConsumerStates(event.event, ack_result);
+      client_->OnTouchEventAck(event, ack_result);
       return;
     }
 
@@ -659,6 +675,12 @@ void TouchEventQueue::OnHasTouchEventHandlers(bool has_handlers) {
   has_handlers_ = has_handlers;
 }
 
+void TouchEventQueue::OnHasTouchMoveEventHandlers(bool has_handlers) {
+  DCHECK(!dispatching_touch_ack_);
+  DCHECK(!dispatching_touch_);
+  has_move_handlers_ = has_handlers;
+}
+
 bool TouchEventQueue::IsPendingAckTouchStart() const {
   DCHECK(!dispatching_touch_ack_);
   if (touch_queue_.empty())
@@ -823,6 +845,9 @@ TouchEventQueue::FilterBeforeForwarding(const WebTouchEvent& event) {
                : ACK_WITH_NO_CONSUMER_EXISTS;
   }
 
+  if (event.type == WebInputEvent::TouchMove && !has_move_handlers_)
+    return ACK_WITH_NO_CONSUMER_EXISTS;
+
   if (has_handler_for_current_sequence_) {
     // Only forward a touch if it has a non-stationary pointer that is active
     // in the current touch sequence.
@@ -868,6 +893,19 @@ void TouchEventQueue::UpdateTouchConsumerStates(const WebTouchEvent& event,
       send_touch_events_async_ = false;
     has_handler_for_current_sequence_ |=
         ack_result != INPUT_EVENT_ACK_STATE_NO_CONSUMER_EXISTS;
+
+    if (WebTouchEventTraits::IsTouchSequenceStart(event)) {
+      if (timeout_handler_ && timeout_handler_->HasTimeoutEvent())
+        LogSequenceHandlerType(UNKNOWN_BECAUSE_TIMEOUT);
+      else if (!has_handlers_)
+        LogSequenceHandlerType(NO_HANDLERS_FOR_PAGE);
+      else if (!has_handler_for_current_sequence_)
+        LogSequenceHandlerType(NO_HANDLER_FOR_SEQUENCE);
+      else if (!has_move_handlers_)
+        LogSequenceHandlerType(HAS_HANDLER_BUT_NO_MOVE_HANDLERS_FOR_PAGE);
+      else
+        LogSequenceHandlerType(HAS_HANDLER);
+    }
   } else if (WebTouchEventTraits::IsTouchSequenceEnd(event)) {
     has_handler_for_current_sequence_ = false;
   }