Properly resume scrolling if a fling ends during a suppressed scroll

content/renderer/input/input_handler_proxy_unittest.cc

Index: content/renderer/input/input_handler_proxy_unittest.cc
diff --git a/content/renderer/input/input_handler_proxy_unittest.cc b/content/renderer/input/input_handler_proxy_unittest.cc
index d932424e9a6a5bad9912caccba17b4432f87a2be..d9ca67ce3895f427d8e9a681ffc0a8efe730ed5b 100644
--- a/content/renderer/input/input_handler_proxy_unittest.cc
+++ b/content/renderer/input/input_handler_proxy_unittest.cc
@@ -1856,5 +1856,75 @@ TEST_F(InputHandlerProxyTest, NoFlingBoostIfFlingTooSlow) {
   VERIFY_AND_RESET_MOCKS();
 }
 
+TEST_F(InputHandlerProxyTest, FlingBoostTerminatedDuringScrollSequence) {
+  base::TimeDelta dt = base::TimeDelta::FromMilliseconds(10);
+  base::TimeTicks time = base::TimeTicks() + dt;
+  base::TimeTicks last_animate_time = time;
+  WebFloatPoint fling_delta = WebFloatPoint(1000, 0);
+  WebPoint fling_point = WebPoint(7, 13);
+  StartFling(
+      time, blink::WebGestureDeviceTouchscreen, fling_delta, fling_point);
+
+  // Now cancel the fling.  The fling cancellation should be deferred to allow
+  // fling boosting events to arrive.
+  time += dt;
+  CancelFling(time);
+
+  // The GestureScrollBegin should be swallowed by the fling.
+  time += dt;
+  gesture_.timeStampSeconds = InSecondsF(time);
+  gesture_.type = WebInputEvent::GestureScrollBegin;
+  EXPECT_CALL(mock_input_handler_,
+              IsCurrentlyScrollingLayerAt(testing::_, testing::_))
+      .WillOnce(testing::Return(true));
+  EXPECT_EQ(expected_disposition_, input_handler_->HandleInputEvent(gesture_));
+
+  VERIFY_AND_RESET_MOCKS();
+
+  // Now animate the fling to completion (in this case, the fling should
+  // terminate because the input handler reports a failed scroll). As the fling
+  // was cancelled during an active scroll sequence, a synthetic
+  // GestureScrollBegin should be processed, resuming the scroll.
+  time += dt;
+  float expected_delta =
+      (time - last_animate_time).InSecondsF() * -fling_delta.x;
+  EXPECT_CALL(mock_input_handler_,
+              ScrollBy(testing::_,
+                       testing::Property(&gfx::Vector2dF::x,
+                                         testing::Eq(expected_delta))))
+      .WillOnce(testing::Return(false));
+  EXPECT_CALL(mock_input_handler_, ScrollEnd());
+  EXPECT_CALL(mock_input_handler_, ScrollBegin(testing::_, testing::_))
+      .WillOnce(testing::Return(cc::InputHandler::ScrollStarted));
+  input_handler_->Animate(time);
+
+  VERIFY_AND_RESET_MOCKS();
+
+  // Subsequent GestureScrollUpdates after the cancelled, boosted fling should
+  // cause scrolling as usual.
+  time += dt;
+  expected_delta = 7.3f;
+  gesture_.timeStampSeconds = InSecondsF(time);
+  gesture_.type = WebInputEvent::GestureScrollUpdate;
+  gesture_.data.scrollUpdate.deltaX = -expected_delta;
+  EXPECT_CALL(mock_input_handler_,
+              ScrollBy(testing::_,
+                       testing::Property(&gfx::Vector2dF::x,
+                                         testing::Eq(expected_delta))))
+      .WillOnce(testing::Return(true));
+  EXPECT_EQ(expected_disposition_, input_handler_->HandleInputEvent(gesture_));
+
+  VERIFY_AND_RESET_MOCKS();
+
+  // GestureScrollEnd should terminate the resumed scroll properly.
+  time += dt;
+  gesture_.timeStampSeconds = InSecondsF(time);
+  gesture_.type = WebInputEvent::GestureScrollEnd;
+  EXPECT_CALL(mock_input_handler_, ScrollEnd());
+  EXPECT_EQ(expected_disposition_, input_handler_->HandleInputEvent(gesture_));
+
+  VERIFY_AND_RESET_MOCKS();
+}
+
 } // namespace
 } // namespace content