Bug 88440 – [chromium] cancel flings on receipt of MouseWheel events

• Component: UI Events
• Status: RESOLVED WONTFIX

[Robert Kroeger]

Permit the browser to reduce the number of GestureFlingCancel events it sends to WebKit by also stopping an in-progress fling on WheelEvent arrival.

[Robert Kroeger]

Created attachment 146117 [details]
Patch

[WebKit Review Bot]

Comment on attachment 146117 [details]
Patch

Attachment 146117 [details] did not pass chromium-ews (chromium-xvfb):
Output: http://queues.webkit.org/results/12907534

New failing tests:
WebCompositorInputHandlerImplTest.gestureFlingAnimates
WebCompositorInputHandlerImplTest.gestureFlingTransferResets

[WebKit Review Bot]

Created attachment 146211 [details]
Archive of layout-test-results from ec2-cr-linux-04

The attached test failures were seen while running run-webkit-tests on the chromium-ews.
Bot: ec2-cr-linux-04  Port: <class 'webkitpy.common.config.ports.ChromiumXVFBPort'>  Platform: Linux-2.6.35-28-virtual-x86_64-with-Ubuntu-10.10-maverick

[Robert Kroeger]

Created attachment 146593 [details]
Patch

[Robert Kroeger]

Created attachment 146596 [details]
Patch

[Robert Kroeger]

Created attachment 146907 [details]
Patch

[Robert Kroeger]

Created attachment 146908 [details]
Patch

[Robert Kroeger]

jamesr@ mind taking a look please?

[WebKit Review Bot]

Attachment 146908 [details] did not pass style-queue:

Failed to run "['Tools/Scripts/check-webkit-style', '--diff-files', u'Source/WebKit/chromium/ChangeLog', u'Sourc..." exit_code: 1
Source/WebKit/chromium/src/WebCompositorInputHandlerImpl.cpp:164:  Weird number of spaces at line-start.  Are you using a 4-space indent?  [whitespace/indent] [3]
Total errors found: 1 in 7 files


If any of these errors are false positives, please file a bug against check-webkit-style.

[James Robinson]

What's the motivation for putting this logic inside WebKit instead of in the embedder?

[Robert Kroeger]

Why in WebKit and not in the browser: the knowledge that a fling is in progress (i.e. there is a curve) is in WebKit.

[James Robinson]

Yes, but WebKit only knows about a subset of the interactions the user is having with the system.  For instance, if a user switches tabs using a keyboard accelerator I would expect that the fling should be cancelled and that WebKit would not necessarily see any of the key events associated with that interaction (since they would be handled browser-side).  In this case we couldn't really cancel the fling from within WebKit unless we taught WebKit about all of the possible side-effects of fling cancelling interactions.

[James Robinson]

Comment on attachment 146908 [details]
Patch

Seems like the wrong direction.

[James Robinson]

Also the browser always knows if it's sent a fling start to WebKit, the only thing the browser does not know is whether that fling has ended "naturally" or needs to be explicitly cancelled.  I think sending a cancelFlingIfInProgress is quite reasonable for the case where the browser doesn't know this information.

[Stephen Chenney]

https://code.google.com/p/chromium/issues/detail?id=231339