gpu: Avoid flinging beyond content edge

gpu: Avoid flinging beyond content edge

If the user flings down a page while the page is still loading, we may
hit a situation where the fling animation stops at the bottom edge of
the content, pauses while the loading proceeds and then continues once the
content grows taller. This results in a jarring pause in an otherwise
continuous animation.

This patch fixes the issue by preventing the fling animation from trying
to scroll beyond the content edge. In other words, as soon as the
content overscrolls on a specific axis, we prevent the fling animation
from scrolling on that axis again.

BUG=244376
TEST=InputHandlerProxyTest.GestureFlingStopsAtContentEdge

Committed: https://src.chromium.org/viewvc/chrome?view=rev&revision=204006

[rjkroege, 2013-05-28 19:27:37]

lgtm

[Sami, 2013-05-31 10:31:06]

Thanks Rob. Al, what do you think about this one?

[apatrick_chromium, 2013-05-31 18:09:49]

Sorry for taking so long I've been OOO. I don't know this code. LGTM for style.

[Sami, 2013-05-31 18:17:35]

Thanks Al. James, mind doing a sanity check?

[jamesr, 2013-05-31 18:23:28]

lgtm

https://codereview.chromium.org/16156002/diff/1/content/renderer/gpu/input_ha...
File content/renderer/gpu/input_handler_proxy.cc (right):

https://codereview.chromium.org/16156002/diff/1/content/renderer/gpu/input_ha...
content/renderer/gpu/input_handler_proxy.cc:308: const int
kFlingOverscrollThreshold = 1;
why not static?

[Sami, 2013-06-03 14:23:59]

On 2013/05/31 18:23:28, jamesr wrote:
> lgtm
> 
>
https://codereview.chromium.org/16156002/diff/1/content/renderer/gpu/input_ha...
> File content/renderer/gpu/input_handler_proxy.cc (right):
> 
>
https://codereview.chromium.org/16156002/diff/1/content/renderer/gpu/input_ha...
> content/renderer/gpu/input_handler_proxy.cc:308: const int
> kFlingOverscrollThreshold = 1;
> why not static?

Well spotted. Done.

[commit-bot: I haz the power, 2013-06-03 14:24:08]

CQ is trying da patch. Follow status at
https://chromium-status.appspot.com/cq/skyostil@chromium.org/16156002/8001

[commit-bot: I haz the power, 2013-06-04 01:59:40]

The commit queue went berserk retrying too often for a
seemingly flaky test on builder android_dbg:
http://build.chromium.org/p/tryserver.chromium/buildstatus?builder=android_db...
http://build.chromium.org/p/tryserver.chromium/buildstatus?builder=android_db...
http://build.chromium.org/p/tryserver.chromium/buildstatus?builder=android_db...
http://build.chromium.org/p/tryserver.chromium/buildstatus?builder=android_db...
http://build.chromium.org/p/tryserver.chromium/buildstatus?builder=android_db...

[commit-bot: I haz the power, 2013-06-04 09:44:33]

CQ is trying da patch. Follow status at
https://chromium-status.appspot.com/cq/skyostil@chromium.org/16156002/8001

[commit-bot: I haz the power, 2013-06-04 09:44:36]

Failed to apply patch for content/renderer/gpu/input_handler_proxy_unittest.cc:
While running patch -p1 --forward --force --no-backup-if-mismatch;
  patching file content/renderer/gpu/input_handler_proxy_unittest.cc
  Hunk #1 FAILED at 996.
  1 out of 1 hunk FAILED -- saving rejects to file
content/renderer/gpu/input_handler_proxy_unittest.cc.rej

Patch:       content/renderer/gpu/input_handler_proxy_unittest.cc
Index: content/renderer/gpu/input_handler_proxy_unittest.cc
diff --git a/content/renderer/gpu/input_handler_proxy_unittest.cc
b/content/renderer/gpu/input_handler_proxy_unittest.cc
index
6be6456c71305c4d9a3fd67dc1ecf35e8af3d28c..813cc5db09496fd9f5cb6d5e9ead069c76a09857
100644
--- a/content/renderer/gpu/input_handler_proxy_unittest.cc
+++ b/content/renderer/gpu/input_handler_proxy_unittest.cc
@@ -996,4 +996,60 @@ TEST_F(InputHandlerProxyTest, LastInputEventForVSync) {
   input_handler_->HandleInputEvent(gesture_);
 }
 
+TEST_F(InputHandlerProxyTest, GestureFlingStopsAtContentEdge) {
+  // We shouldn't send any events to the widget for this gesture.
+  expected_disposition_ = DidHandle;
+  VERIFY_AND_RESET_MOCKS();
+
+  // On the fling start, we should schedule an animation but not actually start
+  // scrolling.
+  gesture_.type = WebInputEvent::GestureFlingStart;
+  WebFloatPoint fling_delta = WebFloatPoint(1000, 1000);
+  gesture_.data.flingStart.velocityX = fling_delta.x;
+  gesture_.data.flingStart.velocityY = fling_delta.y;
+  EXPECT_CALL(mock_input_handler_, ScheduleAnimation());
+  EXPECT_CALL(mock_input_handler_, ScrollBegin(testing::_, testing::_))
+      .WillOnce(testing::Return(cc::InputHandler::ScrollStarted));
+  EXPECT_CALL(mock_input_handler_, ScrollEnd());
+  input_handler_->HandleInputEvent(gesture_);
+  testing::Mock::VerifyAndClearExpectations(&mock_input_handler_);
+
+  // The first animate doesn't cause any scrolling.
+  EXPECT_CALL(mock_input_handler_, ScheduleAnimation());
+  base::TimeTicks time = base::TimeTicks() + base::TimeDelta::FromSeconds(10);
+  input_handler_->Animate(time);
+  testing::Mock::VerifyAndClearExpectations(&mock_input_handler_);
+
+  // The second animate starts scrolling in the positive X and Y directions.
+  EXPECT_CALL(mock_input_handler_, ScheduleAnimation());
+  EXPECT_CALL(mock_input_handler_, ScrollBegin(testing::_, testing::_))
+      .WillOnce(testing::Return(cc::InputHandler::ScrollStarted));
+  EXPECT_CALL(mock_input_handler_,
+              ScrollBy(testing::_,
+                       testing::Property(&gfx::Vector2dF::y, testing::Lt(0))))
+      .WillOnce(testing::Return(true));
+  EXPECT_CALL(mock_input_handler_, ScrollEnd());
+  time += base::TimeDelta::FromMilliseconds(100);
+  input_handler_->Animate(time);
+  testing::Mock::VerifyAndClearExpectations(&mock_input_handler_);
+
+  // Simulate hitting the bottom content edge.
+  gfx::Vector2dF overscroll_amount(0, 100);
+  gfx::Vector2dF overscroll_velocity(0, 10);
+  input_handler_->DidOverscroll(overscroll_amount, overscroll_velocity);
+
+  // The next call to animate will no longer scroll vertically.
+  EXPECT_CALL(mock_input_handler_, ScheduleAnimation());
+  EXPECT_CALL(mock_input_handler_, ScrollBegin(testing::_, testing::_))
+      .WillOnce(testing::Return(cc::InputHandler::ScrollStarted));
+  EXPECT_CALL(mock_input_handler_,
+              ScrollBy(testing::_,
+                       testing::Property(&gfx::Vector2dF::y, testing::Eq(0))))
+      .WillOnce(testing::Return(true));
+  EXPECT_CALL(mock_input_handler_, ScrollEnd());
+  time += base::TimeDelta::FromMilliseconds(100);
+  input_handler_->Animate(time);
+  testing::Mock::VerifyAndClearExpectations(&mock_input_handler_);
+}
+
 }  // namespace

[commit-bot: I haz the power, 2013-06-04 11:09:57]

CQ is trying da patch. Follow status at
https://chromium-status.appspot.com/cq/skyostil@chromium.org/16156002/24001

[commit-bot: I haz the power, 2013-06-04 18:20:29]

Change committed as 204006