REGRESSION (r239441): [iOS] Selection UI sometimes doesn't change after tapping ...
authorwenson_hsieh@apple.com <wenson_hsieh@apple.com@268f45cc-cd09-0410-ab3c-d52691b4dbfc>
Wed, 2 Jan 2019 20:28:24 +0000 (20:28 +0000)
committerwenson_hsieh@apple.com <wenson_hsieh@apple.com@268f45cc-cd09-0410-ab3c-d52691b4dbfc>
Wed, 2 Jan 2019 20:28:24 +0000 (20:28 +0000)
commit24bb0b3557ee4260bc45b589cfdd82322d93cebf
treebed25521e526c034f0fd417c8dc5d4550dfdf012
parentb54c7b3b87d08be21abb90ae941cac9386fd94df
REGRESSION (r239441): [iOS] Selection UI sometimes doesn't change after tapping "select all" in the callout bar
https://bugs.webkit.org/show_bug.cgi?id=193070
<rdar://problem/46921508>

Reviewed by Tim Horton.

Source/WebKit:

r239441 added logic to include an EditorState in the next layer tree commit when refocusing an element; this was
done to ensure that after tapping an element that has already been programmatically focused, we still send up-
to-date editor information to the UI process for the purposes of zooming to the selection rect, even if the
selection in the DOM is unchanged, since other aspects of the editor state may have changed since the element
was initially focused.

We currently try to flag the next layer tree commit by setting `m_hasPendingEditorStateUpdate` to `true`.
However, this is problematic since we aren't guaranteed in all cases that a compositing flush has been
scheduled. In the case where it hasn't, we'll end up in a state where the editor state update flag has been set,
yet the update will not make it over to the UI process until something happens that forces a layer tree commit
(e.g. scrolling, pinch zooming). Worse still, if the selection is then programmatically changed from the web
process, we will bail from sending a subsequent editor state update to the UI process because `WebPage` thinks
that a pending editor state has already been scheduled. This manifests in selection UI not updating after
tapping "Select All" in the callout bar, if the callout bar was brought up by tapping near the selection (since
this refocuses the element).

To fix this, we adjust this logic in `WebPage::elementDidRefocus` so that it sets the flag and then schedules a
compositing flush, but only if the user is actually interacting with the focused element (i.e., if the page
calls `focus` repeatedly, we won't continue to schedule compositing flushes).

Test: editing/selection/ios/change-selection-after-tapping-focused-element.html

* WebProcess/WebPage/WebPage.cpp:
(WebKit::WebPage::elementDidRefocus):
(WebKit::WebPage::sendEditorStateUpdate):
(WebKit::WebPage::scheduleFullEditorStateUpdate):

Add a private helper method to schedule an editor state update by setting `m_hasPendingEditorStateUpdate` to
`true` and then scheduling a compositing layer flush. Also, add a FIXME aluding to the fact that scheduling an
entire compositing layer flush to send an editor state update is somewhat wasteful, and should be replaced by
just scheduling this work to be done before the next frame (see: <rdar://problem/36523583> for more detail).

We also use this helper method in a few places where we currently turn on the editor state flag and schedule a
subsequent compositing flush.

(WebKit::WebPage::sendPartialEditorStateAndSchedulePostLayoutUpdate):
* WebProcess/WebPage/WebPage.h:

LayoutTests:

Add a test to ensure that selection UI is shown after tapping on a focused element and then changing the
selection programmatically.

* editing/selection/ios/change-selection-after-tapping-focused-element-expected.txt: Added.
* editing/selection/ios/change-selection-after-tapping-focused-element.html: Added.

git-svn-id: https://svn.webkit.org/repository/webkit/trunk@239573 268f45cc-cd09-0410-ab3c-d52691b4dbfc
LayoutTests/ChangeLog
LayoutTests/editing/selection/ios/change-selection-after-tapping-focused-element-expected.txt [new file with mode: 0644]
LayoutTests/editing/selection/ios/change-selection-after-tapping-focused-element.html [new file with mode: 0644]
Source/WebKit/ChangeLog
Source/WebKit/WebProcess/WebPage/WebPage.cpp
Source/WebKit/WebProcess/WebPage/WebPage.h