Fix recursion in handling touch input events acks.

content/browser/renderer_host/input/passthrough_touch_event_queue_unittest.cc

Index: content/browser/renderer_host/input/passthrough_touch_event_queue_unittest.cc
diff --git a/content/browser/renderer_host/input/passthrough_touch_event_queue_unittest.cc b/content/browser/renderer_host/input/passthrough_touch_event_queue_unittest.cc
index 833f0ab5fee55ba61af64985edb73fd6085e3fb6..6c1753b27d5ea632aed419b741416bc64540d6b5 100644
--- a/content/browser/renderer_host/input/passthrough_touch_event_queue_unittest.cc
+++ b/content/browser/renderer_host/input/passthrough_touch_event_queue_unittest.cc
@@ -64,15 +64,14 @@ class PassthroughTouchEventQueueTest : public testing::Test,
     sent_events_ids_.push_back(event.event.unique_touch_event_id);
     if (sync_ack_result_) {
       auto sync_ack_result = std::move(sync_ack_result_);
-      SendTouchEventAck(*sync_ack_result);
+      SendTouchEventAckWithID(*sync_ack_result,
+                              event.event.unique_touch_event_id);
     }
   }
 
   void OnTouchEventAck(const TouchEventWithLatencyInfo& event,
                        InputEventAckState ack_result) override {
     ++acked_event_count_;
-    last_acked_event_ = event.event;
-    last_acked_event_state_ = ack_result;
     if (followup_touch_event_) {
       std::unique_ptr<WebTouchEvent> followup_touch_event =
           std::move(followup_touch_event_);
@@ -84,6 +83,8 @@ class PassthroughTouchEventQueueTest : public testing::Test,
       queue_->OnGestureScrollEvent(GestureEventWithLatencyInfo(
           *followup_gesture_event, ui::LatencyInfo()));
     }
+    last_acked_event_ = event.event;
+    last_acked_event_state_ = ack_result;
   }
 
   void OnFilteringTouchEvent(const blink::WebTouchEvent& touch_event) override {
@@ -756,6 +757,46 @@ TEST_F(PassthroughTouchEventQueueTest, SynchronousAcks) {
   EXPECT_EQ(1U, GetAndResetAckedEventCount());
 }
 
+// Tests that touch-events acks are in order even with synchronous acks.
+TEST_F(PassthroughTouchEventQueueTest, SynchronousAcksInOrder) {
+  // TouchStart
+  PressTouchPoint(1, 1);
+  EXPECT_EQ(1U, queued_event_count());
+  EXPECT_EQ(1U, GetAndResetSentEventCount());
+  EXPECT_EQ(0U, GetAndResetAckedEventCount());
+
+  MoveTouchPoint(0, 2, 3);
+  EXPECT_EQ(2U, queued_event_count());
+  EXPECT_EQ(1U, GetAndResetSentEventCount());
+  EXPECT_EQ(0U, GetAndResetAckedEventCount());
+
+  SendTouchEventAckLast(INPUT_EVENT_ACK_STATE_CONSUMED);

[tdresser, 2017/04/18 18:57:02]

Can you comment that this will ack the touchmove, leaving it blocked behind the
touchstart?

[dtapuska, 2017/04/18 19:56:52]

Done.

+  EXPECT_EQ(2U, queued_event_count());
+  EXPECT_EQ(0U, GetAndResetSentEventCount());
+  EXPECT_EQ(0U, GetAndResetAckedEventCount());
+
+  // TouchMove
+  // Ack the touch start, should release two events.
+  // Create a touch event that will be queued synchronously by a touch ack.
+  // Note, this will be triggered by all subsequent touch acks.

[tdresser, 2017/04/18 18:57:02]

I don't quite understand "this will be triggered by all subsequent touch acks".

Won't it be triggered by _the_ subsequent touch ack?

[dtapuska, 2017/04/18 19:56:52]

Done.

+  WebTouchEvent followup_event(
+      WebInputEvent::kTouchMove, WebInputEvent::kNoModifiers,
+      ui::EventTimeStampToSeconds(ui::EventTimeForNow()));
+  followup_event.touches_length = 1;
+  followup_event.touches[0].id = 0;
+  followup_event.unique_touch_event_id = 100;
+  followup_event.touches[0].state = WebTouchPoint::kStateMoved;
+  SetFollowupEvent(followup_event);
+
+  SetSyncAckResult(INPUT_EVENT_ACK_STATE_CONSUMED);
+  SendTouchEventAck(INPUT_EVENT_ACK_STATE_CONSUMED);
+
+  EXPECT_EQ(0U, queued_event_count());
+  EXPECT_EQ(1U, GetAndResetSentEventCount());
+  EXPECT_EQ(3U, GetAndResetAckedEventCount());
+  EXPECT_EQ(100U, acked_event().unique_touch_event_id);
+}
+
 // Tests that followup events triggered by an immediate ack from
 // TouchEventQueue::QueueEvent() are properly handled.
 TEST_F(PassthroughTouchEventQueueTest, ImmediateAckWithFollowupEvents) {