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

content/browser/renderer_host/render_widget_host_unittest.cc

 // Copyright (c) 2012 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "base/basictypes.h"
 #include "base/memory/scoped_ptr.h"
 #include "base/shared_memory.h"
 #include "base/timer.h"
 #include "content/browser/browser_thread_impl.h"
 #include "content/browser/renderer_host/backing_store.h"
@@ skipping 3108 matching lines @@
   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.
+  // 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());
   process_->sink().ClearMessages();
 
   // Receive ACK for the second (coalesced) event as not processed. This will
   // start a back navigation. However, this will also cause the queued next
   // event to be sent to the renderer. But since overscroll navigation has
   // started, that event will also be included in the overscroll computation
   // instead of being sent to the renderer. So the result will be an overscroll
   // back navigation, and no event will be sent to the renderer.
   SendInputEventACK(WebInputEvent::MouseWheel,
                     INPUT_EVENT_ACK_STATE_NOT_CONSUMED);
   EXPECT_EQ(OVERSCROLL_WEST, host_->overscroll_mode());
   EXPECT_EQ(OVERSCROLL_WEST, host_->overscroll_delegate()->current_mode());
   EXPECT_EQ(-75.f, host_->overscroll_delta_x());
   EXPECT_EQ(-25.f, host_->overscroll_delegate()->delta_x());
   EXPECT_EQ(0.f, host_->overscroll_delegate()->delta_y());
   EXPECT_EQ(0U, process_->sink().message_count());
 
   // Send a mouse-move event. This should cancel the overscroll navigation.
   SimulateMouseMove(5, 10, 0);
   EXPECT_EQ(OVERSCROLL_NONE, host_->overscroll_mode());
   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();
   process_->sink().ClearMessages();
 
   // Send a wheel event. ACK the event as not processed. This should not
   // initiate an overscroll gesture since it doesn't cross the threshold yet.
   SimulateWheelEvent(10, -5, 0, true);
   EXPECT_EQ(1U, process_->sink().message_count());
   SendInputEventACK(WebInputEvent::MouseWheel,
@@ skipping 199 matching lines @@
 // controller. This also tests that the overscroll controller and the
 // gesture-event filter play nice with each other.
 TEST_F(RenderWidgetHostTest, GestureScrollOverscrolls) {
   // 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);
+                    INPUT_EVENT_ACK_STATE_NOT_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
   // initiate the navigation gesture.
   SimulateGestureScrollUpdateEvent(55, -5, 0);
   SendInputEventACK(WebInputEvent::GestureScrollUpdate,
                     INPUT_EVENT_ACK_STATE_NOT_CONSUMED);
   EXPECT_EQ(OVERSCROLL_EAST, host_->overscroll_mode());
   EXPECT_EQ(OVERSCROLL_EAST, host_->overscroll_delegate()->current_mode());
@@ skipping 21 matching lines @@
   // the event to the renderer. The gesture-event filter should receive this
   // event.
   SimulateGestureEvent(WebInputEvent::GestureScrollEnd,
                        WebGestureEvent::Touchscreen);
   EXPECT_EQ(OVERSCROLL_NONE, host_->overscroll_mode());
   EXPECT_EQ(OVERSCROLL_NONE, host_->overscroll_delegate()->current_mode());
   EXPECT_EQ(1U, process_->sink().message_count());
   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) {
   host_->SetupForOverscrollControllerTest();
   host_->set_debounce_interval_time_ms(100);
   process_->sink().ClearMessages();
 
   // Start scrolling. Receive ACK as it being processed.
   SimulateGestureEvent(WebInputEvent::GestureScrollBegin,
                        WebGestureEvent::Touchscreen);
@@ skipping 436 matching lines @@
   EXPECT_EQ(1U, process_->sink().message_count());
   EXPECT_TRUE(process_->sink().GetUniqueMessageMatching(
                   InputMsg_HandleInputEvent::ID));
   process_->sink().ClearMessages();
 
   // Check that the correct unhandled wheel event was received.
   EXPECT_EQ(view_->unhandled_wheel_event().deltaY, -5);
 }
 
 }  // namespace content