overscroll: Do not overscroll if the beginning of a scroll was consumed.

content/browser/renderer_host/render_widget_host_unittest.cc

Index: content/browser/renderer_host/render_widget_host_unittest.cc
diff --git a/content/browser/renderer_host/render_widget_host_unittest.cc b/content/browser/renderer_host/render_widget_host_unittest.cc
index 60360caeecf3d95d39187272cdb110f3be5d7ddf..fd0be0a8a206fb87e0bd70e46eaa564b470f8f01 100644
--- a/content/browser/renderer_host/render_widget_host_unittest.cc
+++ b/content/browser/renderer_host/render_widget_host_unittest.cc
@@ -3126,9 +3126,9 @@ TEST_F(RenderWidgetHostTest, WheelScrollEventOverscrolls) {
   EXPECT_EQ(1U, process_->sink().message_count());
   process_->sink().ClearMessages();
 
-  // Receive ACK the first wheel event as processed.
+  // Receive ACK the first wheel event as not processed.
   SendInputEventACK(WebInputEvent::MouseWheel,
-                    INPUT_EVENT_ACK_STATE_CONSUMED);
+                    INPUT_EVENT_ACK_STATE_NOT_CONSUMED);
   EXPECT_EQ(OVERSCROLL_NONE, host_->overscroll_mode());
   EXPECT_EQ(OVERSCROLL_NONE, host_->overscroll_delegate()->current_mode());
   EXPECT_EQ(1U, process_->sink().message_count());
@@ -3155,6 +3155,75 @@ TEST_F(RenderWidgetHostTest, WheelScrollEventOverscrolls) {
   EXPECT_EQ(OVERSCROLL_NONE, host_->overscroll_delegate()->current_mode());
 }
 
+// Tests that if some scroll events are consumed towards the start, then
+// subsequent scrolls do not overscroll.
+TEST_F(RenderWidgetHostTest, WheelScrollConsumedDoNotOverscroll) {
+  host_->SetupForOverscrollControllerTest();
+  process_->sink().ClearMessages();
+
+  // Simulate wheel events.
+  SimulateWheelEvent(0, -5, 0, true);  // sent directly
+  SimulateWheelEvent(0, -1, 0, true);  // enqueued
+  SimulateWheelEvent(-10, -3, 0, true);  // coalesced into previous event
+  SimulateWheelEvent(-15, -1, 0, true);  // coalesced into previous event
+  SimulateWheelEvent(-30, -3, 0, true);  // coalesced into previous event
+  SimulateWheelEvent(-20, 6, 1, true);  // enqueued, different modifiers
+  EXPECT_EQ(OVERSCROLL_NONE, host_->overscroll_mode());
+  EXPECT_EQ(1U, process_->sink().message_count());
+  process_->sink().ClearMessages();
+
+  // Receive ACK the first wheel event as processed.
+  SendInputEventACK(WebInputEvent::MouseWheel,
+                    INPUT_EVENT_ACK_STATE_CONSUMED);
+  EXPECT_EQ(OVERSCROLL_NONE, host_->overscroll_mode());
+  EXPECT_EQ(OVERSCROLL_NONE, host_->overscroll_delegate()->current_mode());
+  EXPECT_EQ(1U, process_->sink().message_count());
+  process_->sink().ClearMessages();
+
+  // Receive ACK for the second (coalesced) event as not processed. This should
+  // not initiate overscroll, since the beginning of the scroll has been
+  // consumed. The queued event with different modifiers should be sent to the
+  // renderer.
+  SendInputEventACK(WebInputEvent::MouseWheel,
+                    INPUT_EVENT_ACK_STATE_NOT_CONSUMED);
+  EXPECT_EQ(OVERSCROLL_NONE, host_->overscroll_mode());
+  EXPECT_EQ(1U, process_->sink().message_count());
+
+  process_->sink().ClearMessages();
+  SendInputEventACK(WebInputEvent::MouseWheel,
+                    INPUT_EVENT_ACK_STATE_NOT_CONSUMED);
+  EXPECT_EQ(0U, process_->sink().message_count());
+  EXPECT_EQ(OVERSCROLL_NONE, host_->overscroll_mode());
+
+  // Indicate the end of the scrolling from the touchpad.
+  SimulateGestureFlingStartEvent(-1200.f, 0.f, WebGestureEvent::Touchpad);
+  EXPECT_EQ(1U, process_->sink().message_count());
+
+  // Start another scroll. This time, do not consume any scroll events.
+  process_->sink().ClearMessages();
+  SimulateWheelEvent(0, -5, 0, true);  // sent directly
+  SimulateWheelEvent(0, -1, 0, true);  // enqueued
+  SimulateWheelEvent(-10, -3, 0, true);  // coalesced into previous event
+  SimulateWheelEvent(-15, -1, 0, true);  // coalesced into previous event
+  SimulateWheelEvent(-30, -3, 0, true);  // coalesced into previous event
+  SimulateWheelEvent(-20, 6, 1, true);  // enqueued, different modifiers
+  EXPECT_EQ(OVERSCROLL_NONE, host_->overscroll_mode());
+  EXPECT_EQ(1U, process_->sink().message_count());
+  process_->sink().ClearMessages();
+
+  // Receive ACK for the first wheel and the subsequent coalesced event as not
+  // processed. This should start a back-overscroll.
+  SendInputEventACK(WebInputEvent::MouseWheel,
+                    INPUT_EVENT_ACK_STATE_NOT_CONSUMED);
+  EXPECT_EQ(OVERSCROLL_NONE, host_->overscroll_mode());
+  EXPECT_EQ(OVERSCROLL_NONE, host_->overscroll_delegate()->current_mode());
+  EXPECT_EQ(1U, process_->sink().message_count());
+  process_->sink().ClearMessages();
+  SendInputEventACK(WebInputEvent::MouseWheel,
+                    INPUT_EVENT_ACK_STATE_NOT_CONSUMED);
+  EXPECT_EQ(OVERSCROLL_WEST, host_->overscroll_mode());
+}
+
 // Tests that wheel-scrolling correctly turns overscroll on and off.
 TEST_F(RenderWidgetHostTest, WheelScrollOverscrollToggle) {
   host_->SetupForOverscrollControllerTest();
@@ -3374,13 +3443,8 @@ TEST_F(RenderWidgetHostTest, GestureScrollOverscrolls) {
 
   SimulateGestureEvent(WebInputEvent::GestureScrollBegin,
                        WebGestureEvent::Touchscreen);
-  SimulateGestureScrollUpdateEvent(8, -5, 0);
-
-  // ACK both events as being processed.
   SendInputEventACK(WebInputEvent::GestureScrollBegin,
-                    INPUT_EVENT_ACK_STATE_CONSUMED);
-  SendInputEventACK(WebInputEvent::GestureScrollUpdate,
-                    INPUT_EVENT_ACK_STATE_CONSUMED);
+                    INPUT_EVENT_ACK_STATE_NOT_CONSUMED);
   EXPECT_EQ(OVERSCROLL_NONE, host_->overscroll_mode());
   EXPECT_EQ(OVERSCROLL_NONE, host_->overscroll_delegate()->current_mode());
 
@@ -3422,6 +3486,36 @@ TEST_F(RenderWidgetHostTest, GestureScrollOverscrolls) {
   EXPECT_EQ(1U, host_->GestureEventLastQueueEventSize());
 }
 
+// Tests that if the page is scrolled because of a scroll-gesture, then that
+// particular scroll sequence never generates overscroll, even if there is no
+// content to scroll on the page anymore.
+TEST_F(RenderWidgetHostTest, GestureScrollConsumedDoNotOverscroll) {
+  // Turn off debounce handling for test isolation.
+  host_->SetupForOverscrollControllerTest();
+  host_->set_debounce_interval_time_ms(0);
+  process_->sink().ClearMessages();
+
+  SimulateGestureEvent(WebInputEvent::GestureScrollBegin,
+                       WebGestureEvent::Touchscreen);
+  SimulateGestureScrollUpdateEvent(8, -5, 0);
+
+  // ACK both events as being processed.
+  SendInputEventACK(WebInputEvent::GestureScrollBegin,
+                    INPUT_EVENT_ACK_STATE_CONSUMED);
+  SendInputEventACK(WebInputEvent::GestureScrollUpdate,
+                    INPUT_EVENT_ACK_STATE_CONSUMED);
+  EXPECT_EQ(OVERSCROLL_NONE, host_->overscroll_mode());
+  EXPECT_EQ(OVERSCROLL_NONE, host_->overscroll_delegate()->current_mode());
+
+  // Send another gesture event and ACK as not being processed. This should
+  // not initiate overscroll because the beginning of the scroll event did
+  // scroll some content on the page.
+  SimulateGestureScrollUpdateEvent(55, -5, 0);
+  SendInputEventACK(WebInputEvent::GestureScrollUpdate,
+                    INPUT_EVENT_ACK_STATE_NOT_CONSUMED);
+  EXPECT_EQ(OVERSCROLL_NONE, host_->overscroll_mode());
+}
+
 // Tests that the overscroll controller plays nice with touch-scrolls and the
 // gesture event filter with debounce filtering turned on.
 TEST_F(RenderWidgetHostTest, GestureScrollDebounceOverscrolls) {