Avoid sending touchmove events where all pointers are stationary

It is possible that all the pointers in a given TouchMove may have
state as StateMoved, even though none of the pointers have not
changed in real. Now, TouchEventQueue filters these events and
avoids sending the events to the renderer.

BUG=452032

Review URL: https://codereview.chromium.org/916103002

Cr-Commit-Position: refs/heads/master@{#316609}

5 files changed, 86 insertions, 40 deletions

diff --git a/content/browser/renderer_host/input/input_router_impl_unittest.cc b/content/browser/renderer_host/input/input_router_impl_unittest.cc
index c1619fe..d285cef 100644
--- a/content/browser/renderer_host/input/input_router_impl_unittest.cc
+++ b/content/browser/renderer_host/input/input_router_impl_unittest.cc
@@ -1302,7 +1302,7 @@ TEST_F(InputRouterImplTest,
   EXPECT_EQ(1U, ack_handler_->GetAndResetAckCount());
   EXPECT_FALSE(TouchEventTimeoutEnabled());
 
-  MoveTouchPoint(0, 1, 1);
+  MoveTouchPoint(0, 1, 2);
   SendTouchEvent();
   EXPECT_FALSE(TouchEventTimeoutEnabled());
   EXPECT_EQ(1U, GetSentMessageCountAndResetSink());
diff --git a/content/browser/renderer_host/input/touch_event_queue.cc b/content/browser/renderer_host/input/touch_event_queue.cc
index 6adc661..6bc5cb9 100644
--- a/content/browser/renderer_host/input/touch_event_queue.cc
+++ b/content/browser/renderer_host/input/touch_event_queue.cc
@@ -46,14 +46,15 @@ bool ShouldTouchTriggerTimeout(const WebTouchEvent& event) {
 }
 
 // Compare all properties of touch points to determine the state.
-bool HasPointChanged(const WebTouchPoint& last_point,
-    const WebTouchPoint& current_point) {
-  if (last_point.screenPosition != current_point.screenPosition ||
-      last_point.position != current_point.position ||
-      last_point.radiusX != current_point.radiusX ||
-      last_point.radiusY != current_point.radiusY ||
-      last_point.rotationAngle != current_point.rotationAngle ||
-      last_point.force != current_point.force) {
+bool HasPointChanged(const WebTouchPoint& point_1,
+    const WebTouchPoint& point_2) {
+  DCHECK_EQ(point_1.id, point_2.id);
+  if (point_1.screenPosition != point_2.screenPosition ||
+      point_1.position != point_2.position ||
+      point_1.radiusX != point_2.radiusX ||
+      point_1.radiusY != point_2.radiusY ||
+      point_1.rotationAngle != point_2.rotationAngle ||
+      point_1.force != point_2.force) {
     return true;
   }
   return false;
@@ -729,9 +730,24 @@ TouchEventQueue::FilterBeforeForwarding(const WebTouchEvent& event) {
         continue;
 
       for (size_t j = 0; j < last_sent_touchevent_->touchesLength; ++j) {
-        if (point.id == last_sent_touchevent_->touches[j].id)
+        if (point.id != last_sent_touchevent_->touches[j].id)
+          continue;
+
+        if (event.type != WebInputEvent::TouchMove)
+          return FORWARD_TO_RENDERER;
+
+        // All pointers in TouchMove events may have state as StateMoved,
+        // even though none of the pointers have not changed in real.
+        // Forward these events when at least one pointer has changed.
+        if (HasPointChanged(last_sent_touchevent_->touches[j], point))
           return FORWARD_TO_RENDERER;
+
+        // This is a TouchMove event for which we have yet to find a
+        // non-stationary pointer. Continue checking the next pointers
+        // in the |event|.
+        break;
       }
+
     }
   }
 
diff --git a/content/browser/renderer_host/input/touch_event_queue_unittest.cc b/content/browser/renderer_host/input/touch_event_queue_unittest.cc
index 8d50b0b..597357f 100644
--- a/content/browser/renderer_host/input/touch_event_queue_unittest.cc
+++ b/content/browser/renderer_host/input/touch_event_queue_unittest.cc
@@ -1438,7 +1438,7 @@ TEST_F(TouchEventQueueTest, NoTouchMoveSuppressionAfterMultiTouch) {
   EXPECT_EQ(1U, GetAndResetAckedEventCount());
 
   // TouchMove with a secondary pointer should not be suppressed.
-  MoveTouchPoint(1, kSlopLengthDips, 0);
+  MoveTouchPoint(1, kSlopLengthDips+1, 0);
   EXPECT_EQ(1U, queued_event_count());
   EXPECT_EQ(1U, GetAndResetSentEventCount());
   SendTouchEventAck(INPUT_EVENT_ACK_STATE_NOT_CONSUMED);
@@ -1528,7 +1528,7 @@ TEST_F(TouchEventQueueTest, AsyncTouch) {
    SendGestureEventAck(WebInputEvent::GestureScrollUpdate,
                        INPUT_EVENT_ACK_STATE_NOT_CONSUMED);
 
-   MoveTouchPoint(0, 10, 5);
+   MoveTouchPoint(0, 10, 5+i);
    SendTouchEventAck(INPUT_EVENT_ACK_STATE_NOT_CONSUMED);
    EXPECT_FALSE(HasPendingAsyncTouchMove());
    EXPECT_TRUE(sent_event().cancelable);
@@ -1538,7 +1538,7 @@ TEST_F(TouchEventQueueTest, AsyncTouch) {
    // Consuming a scroll event will throttle subsequent touchmoves.
    SendGestureEventAck(WebInputEvent::GestureScrollUpdate,
                        INPUT_EVENT_ACK_STATE_CONSUMED);
-   MoveTouchPoint(0, 10, 5);
+   MoveTouchPoint(0, 10, 7+i);
    SendTouchEventAck(INPUT_EVENT_ACK_STATE_NOT_CONSUMED);
    EXPECT_TRUE(HasPendingAsyncTouchMove());
    EXPECT_EQ(0U, queued_event_count());
@@ -1629,7 +1629,7 @@ TEST_F(TouchEventQueueTest, AsyncTouchThrottledAfterScroll) {
   EXPECT_EQ(1U, GetAndResetSentEventCount());
   EXPECT_EQ(1U, GetAndResetAckedEventCount());
 
-  MoveTouchPoint(0, 0, 5);
+  MoveTouchPoint(0, 0, 6);
   followup_scroll.type = WebInputEvent::GestureScrollUpdate;
   SetFollowupEvent(followup_scroll);
   SendTouchEventAck(INPUT_EVENT_ACK_STATE_NOT_CONSUMED);
@@ -1707,11 +1707,11 @@ TEST_F(TouchEventQueueTest, AsyncTouchThrottledAfterScroll) {
 
   // The pending touchmove should be coalesced with the next (now synchronous)
   // touchmove.
-  MoveTouchPoint(0, 0, 25);
+  MoveTouchPoint(0, 0, 26);
   EXPECT_TRUE(sent_event().cancelable);
   EXPECT_FALSE(HasPendingAsyncTouchMove());
   EXPECT_EQ(WebInputEvent::TouchMove, sent_event().type);
-  EXPECT_EQ(WebTouchPoint::StateStationary, sent_event().touches[0].state);
+  EXPECT_EQ(WebTouchPoint::StateMoved, sent_event().touches[0].state);
   EXPECT_EQ(WebTouchPoint::StateMoved, sent_event().touches[1].state);
   EXPECT_EQ(1U, queued_event_count());
   EXPECT_EQ(1U, GetAndResetSentEventCount());
@@ -2192,28 +2192,69 @@ TEST_F(TouchEventQueueTest, PointerStatesWhenOtherThanPositionChanged) {
 
   // Change touch point rotationAngle.
   ChangeTouchPointRotationAngle(0, 1.1f);
+  SendTouchEventAck(INPUT_EVENT_ACK_STATE_CONSUMED);
 
   // TouchMove is sent. Test for pointer state.
   const WebTouchEvent& event3 = sent_event();
   EXPECT_EQ(WebInputEvent::TouchMove, event3.type);
   EXPECT_EQ(WebTouchPoint::StateMoved, event3.touches[0].state);
 
-  // TODO(jdduke): Now trying to forward a TouchMove event without really
-  // changing touch point properties. Update below test with testing for
-  // rejected TouchMove with ack state INPUT_EVENT_ACK_STATE_NOT_CONSUMED,
-  // crbug.com/452032. Or should it be in a separte test?.
+  EXPECT_EQ(0U, queued_event_count());
+  EXPECT_EQ(4U, GetAndResetSentEventCount());
+  EXPECT_EQ(4U, GetAndResetAckedEventCount());
+}
 
-  // Do not change any properties, but use previous values.
-  MoveTouchPoint(0, 1.f, 1.f);
-  ChangeTouchPointRadius(0, 1.5f, 1.f);
+// Tests that TouchMoves are filtered when none of the points are changed.
+TEST_F(TouchEventQueueTest, FilterTouchMovesWhenNoPointerChanged) {
+  PressTouchPoint(1, 1);
+  PressTouchPoint(2, 2);
+  SendTouchEventAck(INPUT_EVENT_ACK_STATE_CONSUMED);
+  SendTouchEventAck(INPUT_EVENT_ACK_STATE_CONSUMED);
+  EXPECT_EQ(0U, queued_event_count());
+  EXPECT_EQ(2U, GetAndResetSentEventCount());
+  EXPECT_EQ(2U, GetAndResetAckedEventCount());
+
+  // Move 1st touch point.
+  MoveTouchPoint(0, 10, 10);
+  EXPECT_EQ(1U, queued_event_count());
+  EXPECT_EQ(1U, GetAndResetSentEventCount());
+  EXPECT_EQ(0U, GetAndResetAckedEventCount());
+
+  // TouchMove should be allowed and test for touches state.
+  const WebTouchEvent& event1 = sent_event();
+  EXPECT_EQ(WebInputEvent::TouchMove, event1.type);
+  EXPECT_EQ(WebTouchPoint::StateMoved, event1.touches[0].state);
+  EXPECT_EQ(WebTouchPoint::StateStationary, event1.touches[1].state);
 
-  // Receive an ACK for previous TouchMove.
+  // Do not really move any touch points, but use previous values.
+  MoveTouchPoint(0, 10, 10);
+  ChangeTouchPointRadius(1, 1, 1);
+  MoveTouchPoint(1, 2, 2);
+  EXPECT_EQ(2U, queued_event_count());
+  EXPECT_EQ(0U, GetAndResetSentEventCount());
+
+  // Receive an ACK for 1st TouchMove.
   SendTouchEventAck(INPUT_EVENT_ACK_STATE_CONSUMED);
 
-  // TouchMove is sent, but pointer state should be StateStationary.
-  const WebTouchEvent& event4 = sent_event();
-  EXPECT_EQ(WebInputEvent::TouchMove, event4.type);
-  EXPECT_EQ(WebTouchPoint::StateStationary, event4.touches[0].state);
+  // Tries to forward TouchMove but should be filtered
+  // when none of the touch points have changed.
+  EXPECT_EQ(0U, queued_event_count());
+  EXPECT_EQ(0U, GetAndResetSentEventCount());
+  EXPECT_EQ(4U, GetAndResetAckedEventCount());
+  EXPECT_EQ(INPUT_EVENT_ACK_STATE_NO_CONSUMER_EXISTS, acked_event_state());
+
+  // Move 2nd touch point.
+  MoveTouchPoint(1, 3, 3);
+  SendTouchEventAck(INPUT_EVENT_ACK_STATE_CONSUMED);
+  EXPECT_EQ(0U, queued_event_count());
+  EXPECT_EQ(1U, GetAndResetSentEventCount());
+  EXPECT_EQ(1U, GetAndResetAckedEventCount());
+
+  // TouchMove should be allowed and test for touches state.
+  const WebTouchEvent& event2 = sent_event();
+  EXPECT_EQ(WebInputEvent::TouchMove, event2.type);
+  EXPECT_EQ(WebTouchPoint::StateStationary, event2.touches[0].state);
+  EXPECT_EQ(WebTouchPoint::StateMoved, event2.touches[1].state);
 }
 
 }  // namespace content
diff --git a/content/common/input/touch_event_stream_validator.cc b/content/common/input/touch_event_stream_validator.cc
index 324e47a..4c75989 100644
--- a/content/common/input/touch_event_stream_validator.cc
+++ b/content/common/input/touch_event_stream_validator.cc
@@ -139,12 +139,6 @@ bool TouchEventStreamValidator::Validate(const WebTouchEvent& event,
         break;
 
       case WebTouchPoint::StateStationary:
-        // TODO(jdduke): Remove this after implementing TouchMove events
-        // filtering based on corrected touches state in TouchEventQueue,
-        // crbug.com/452032.
-        if (event.type == WebInputEvent::TouchMove)
-          found_valid_state_for_type = true;
-
         break;
 
       case WebTouchPoint::StateCancelled:
diff --git a/content/common/input/touch_event_stream_validator_unittest.cc b/content/common/input/touch_event_stream_validator_unittest.cc
index fef7379..5e3b767 100644
--- a/content/common/input/touch_event_stream_validator_unittest.cc
+++ b/content/common/input/touch_event_stream_validator_unittest.cc
@@ -159,12 +159,7 @@ TEST(TouchEventStreamValidator, InvalidPointStates) {
          j <= WebTouchPoint::StateCancelled;
          ++j) {
       event.touches[0].state = static_cast<WebTouchPoint::State>(j);
-      if (event.touches[0].state == kValidTouchPointStatesForType[i]
-          // TODO(jdduke): Remove this StateStationary workaround check for
-          // TouchMove after implementing TouchMove events filtering based on
-          // corrected touches state in TouchEventQueue, crbug.com/452032.
-          || (event.type == WebInputEvent::TouchMove
-              && event.touches[0].state == WebTouchPoint::StateStationary)) {
+      if (event.touches[0].state == kValidTouchPointStatesForType[i]) {
         EXPECT_TRUE(validator.Validate(event, &error_msg));
         EXPECT_TRUE(error_msg.empty());
       } else {