Previously cleared text reappears when typing in Korean after tapping ⨯ in Google search field

[whsieh]

e03c81a

Previously cleared text reappears when typing in Korean after tapping ⨯ in Google search field
https://bugs.webkit.org/show_bug.cgi?id=285175
rdar://131897908

Reviewed by NOBODY (OOPS!).

When using Korean keyboards to search on Google (typing in a `textarea` element) on Google on iOS,
if you:

(1) Type some Korean text (stopping in the middle of a composed word).
(2) Tap the ⨯ button, which programmatically clears the text field.
(3) Continue typing on Korean.

...text that was previously typed and then cleared during (2) will reappear. This happens because
there's no mechanism to invalidate and update the keyboard's text entry context when text content
changes programmatically, so the stored input context ends up being reinserted.

To fix this, we add a heuristic to respond to programmatic changes in text content that cause the
value of focused text form controls to become empty, and `-invalidateTextEntryContextForTextInput:`
in the UI process. While we could potentially apply this treatment to *all* programmatic value
changes, this poses a more significant web compat and performance risk.

* LayoutTests/editing/input/ios/invalidate-text-entry-context-when-clearing-text-area-expected.txt: Added.
* LayoutTests/editing/input/ios/invalidate-text-entry-context-when-clearing-text-area.html: Added.

Add a layout test to exercise this change, by teaching the test runner to count the number of times
`-[_UIKeyboardStateManager updateForChangedSelection]` is invoked and verifying that clearing the
text in a `textarea` calls into this method.

* LayoutTests/resources/ui-helper.js:
(window.UIHelper.async keyboardUpdateForChangedSelectionCount):
(window.UIHelper):
* Source/WebCore/html/HTMLInputElement.cpp:
(WebCore::HTMLInputElement::setValue):

Call the new client hook below, when the value is set to the empty string from bindings.

* Source/WebCore/html/HTMLTextAreaElement.cpp:
(WebCore::HTMLTextAreaElement::setValueCommon):
* Source/WebCore/page/ChromeClient.h:
(WebCore::ChromeClient::didProgrammaticallyClearTextFormControl):

Add a client hook to notify `WebPage` when a text form control's text value is cleared.

* Source/WebKit/UIProcess/PageClient.h:
* Source/WebKit/UIProcess/WebPageProxy.h:
* Source/WebKit/UIProcess/WebPageProxy.messages.in:
* Source/WebKit/UIProcess/ios/PageClientImplIOS.h:
* Source/WebKit/UIProcess/ios/PageClientImplIOS.mm:
(WebKit::PageClientImpl::didProgrammaticallyClearFocusedElement):
* Source/WebKit/UIProcess/ios/WKContentViewInteraction.h:
* Source/WebKit/UIProcess/ios/WKContentViewInteraction.mm:
(-[WKContentView _updateInputContextAfterBlurringAndRefocusingElement]):
(-[WKContentView _didProgrammaticallyClearFocusedElement:]):
(-[WKContentView _internalInvalidateTextEntryContext]):
* Source/WebKit/UIProcess/ios/WebPageProxyIOS.mm:
(WebKit::WebPageProxy::didProgrammaticallyClearFocusedElement):
* Source/WebKit/WebProcess/WebCoreSupport/WebChromeClient.cpp:
(WebKit::WebChromeClient::didProgrammaticallyClearTextFormControl):
* Source/WebKit/WebProcess/WebCoreSupport/WebChromeClient.h:
* Source/WebKit/WebProcess/WebPage/WebPage.cpp:
(WebKit::WebPage::contextForElement const):

Make this method const, so that we can pass in the form control element below.

* Source/WebKit/WebProcess/WebPage/WebPage.h:
(WebKit::WebPage::didProgrammaticallyClearTextFormControl):
* Source/WebKit/WebProcess/WebPage/ios/WebPageIOS.mm:
(WebKit::WebPage::didProgrammaticallyClearTextFormControl):

Notify the UI process when the focused form control value is cleared. The IPC message is sent on the
next runloop, so that we'll still invalidate the text entry context in the case where a focused
element is blurred and immediately refocused.

* Tools/TestRunnerShared/UIScriptContext/Bindings/UIScriptController.idl:
* Tools/TestRunnerShared/UIScriptContext/UIScriptController.h:
(WTR::UIScriptController::keyboardUpdateForChangedSelectionCount const):
* Tools/WebKitTestRunner/TestController.h:
* Tools/WebKitTestRunner/ios/TestControllerIOS.mm:
(-[NSObject swizzled_updateForChangedSelection]):
(WTR::TestController::platformInitialize):
(WTR::TestController::keyboardUpdateForChangedSelectionCount const):
* Tools/WebKitTestRunner/ios/UIScriptControllerIOS.h:
* Tools/WebKitTestRunner/ios/UIScriptControllerIOS.mm:
(WTR::UIScriptControllerIOS::keyboardUpdateForChangedSelectionCount const):

Add test infrastructure to keep track of the number of times `-updateForChangedSelection` is
invoked; also expose a new script controller hook to request this count from layout tests.

e03c81a

Misc	iOS, visionOS, tvOS & watchOS	macOS	Linux	Windows
✅ 🧪 style	✅ 🛠 ios	✅ 🛠 mac	✅ 🛠 wpe	✅ 🛠 win
✅ 🧪 bindings	✅ 🛠 ios-sim	✅ 🛠 mac-AS-debug	🧪 wpe-wk2	🧪 win-tests
✅ 🧪 webkitperl	🧪 ios-wk2	🧪 api-mac	✅ 🧪 api-wpe
	🧪 ios-wk2-wpt	🧪 mac-wk1	✅ 🛠 wpe-cairo
	🧪 api-ios	🧪 mac-wk2	✅ 🛠 gtk
	✅ 🛠 vision	🧪 mac-AS-debug-wk2	🧪 gtk-wk2
	✅ 🛠 vision-sim	🧪 mac-wk2-stress	🧪 api-gtk
	✅ 🧪 vision-wk2	🧪 mac-intel-wk2	✅ 🛠 playstation
	✅ 🛠 tv	🛠 mac-safer-cpp
	✅ 🛠 tv-sim
	✅ 🛠 watch
	✅ 🛠 watch-sim

[webkit-early-warning-system]

EWS run on current version of this PR (hash e03c81a)

Details

Misc	iOS, visionOS, tvOS & watchOS	macOS	Linux	Windows
✅ 🧪 style	✅ 🛠 ios	✅ 🛠 mac	✅ 🛠 wpe	✅ 🛠 win
✅ 🧪 bindings	✅ 🛠 ios-sim	✅ 🛠 mac-AS-debug	✅ 🧪 wpe-wk2	✅ 🧪 win-tests
✅ 🧪 webkitperl	🧪 ios-wk2	🧪 api-mac	✅ 🧪 api-wpe
	🧪 ios-wk2-wpt	🧪 mac-wk1	✅ 🛠 wpe-cairo
	🧪 api-ios	🧪 mac-wk2	✅ 🛠 gtk
	✅ 🛠 vision	✅ 🧪 mac-AS-debug-wk2	✅ 🧪 gtk-wk2
	✅ 🛠 vision-sim	🧪 mac-wk2-stress	✅ 🧪 api-gtk
✅ 🛠 🧪 merge	✅ 🧪 vision-wk2	🧪 mac-intel-wk2	✅ 🛠 playstation
	✅ 🛠 tv	✅ 🛠 mac-safer-cpp
	✅ 🛠 tv-sim
	✅ 🛠 watch
	✅ 🛠 watch-sim