Make it possible to test non-stable-state scrolling on iOS

Make it possible to test non-stable-state scrolling on iOS
https://bugs.webkit.org/show_bug.cgi?id=164905

Reviewed by Dan Bernstein.

Source/WebKit2:

Make it possible for an iOS layout test to force every visible rect update
from the UI process to the web process to be in a non-stable state. This emulates
what happens during panning and zooming interactions, and allows us to test the
scrolling and layer trees in these transient states.

This is done by adding a testing property on WKWebView, _stableStateOverride, whose
getters and setters are overridden in TestRunnerWKWebView. When non-nil, we _updateVisibleContentRectAfterScrollInView
consults the NSNumber's boolValue and uses it to override the stable state.

To facilitate this kind of testing, also add immediateScrollToOffset() and
immediateZoomToScale() to UIScriptController. Finally, add doAfterPresentationUpdate()
which provides a callback that fires after one trip to the web process and back.

* UIProcess/API/Cocoa/WKWebView.mm:
(-[WKWebView _updateVisibleContentRectAfterScrollInView:]):
(-[WKWebView _stableStateOverride]):
(-[WKWebView _setStableStateOverride:]):
* UIProcess/API/Cocoa/WKWebViewPrivate.h:

Tools:

Make it possible for an iOS layout test to force every visible rect update
from the UI process to the web process to be in a non-stable state. This emulates
what happens during panning and zooming interactions, and allows us to test the
scrolling and layer trees in these transient states.

This is done by adding a testing property on WKWebView, _stableStateOverride, whose
getters and setters are overridden in TestRunnerWKWebView. When non-nil, we _updateVisibleContentRectAfterScrollInView
consults the NSNumber's boolValue and uses it to override the stable state.

To facilitate this kind of testing, also add immediateScrollToOffset() and
immediateZoomToScale() to UIScriptController. Finally, add doAfterPresentationUpdate()
which provides a callback that fires after one trip to the web process and back.

Add code generation support for optional boolean attributes in IDL.

Align CodeGeneratorDumpRenderTree.pm and CodeGeneratorTestRunner.pm.

* DumpRenderTree/Bindings/CodeGeneratorDumpRenderTree.pm:
(_generateImplementationFile):
(_platformTypeConstructor):
(_returnExpression):
* DumpRenderTree/ios/UIScriptControllerIOS.mm:
(WTR::UIScriptController::doAfterPresentationUpdate):
(WTR::contentOffsetBoundedInValidRange):
(WTR::UIScriptController::scrollToOffset):
(WTR::UIScriptController::immediateScrollToOffset):
(WTR::UIScriptController::immediateZoomToScale):
(WTR::UIScriptController::stableStateOverride):
(WTR::UIScriptController::setStableStateOverride):
* DumpRenderTree/mac/UIScriptControllerMac.mm:
(WTR::UIScriptController::doAfterPresentationUpdate):
* TestRunnerShared/Bindings/JSWrappable.h:
(WTR::JSValueMakeBooleanOrNull):
(WTR::JSValueToNullableBoolean):
* TestRunnerShared/UIScriptContext/Bindings/UIScriptController.idl:
* TestRunnerShared/UIScriptContext/UIScriptController.cpp:
(WTR::UIScriptController::immediateScrollToOffset):
(WTR::UIScriptController::immediateZoomToScale):
(WTR::UIScriptController::stableStateOverride):
(WTR::UIScriptController::setStableStateOverride):
* TestRunnerShared/UIScriptContext/UIScriptController.h:
* WebKitTestRunner/InjectedBundle/Bindings/CodeGeneratorTestRunner.pm:
(_classRefGetter):
(_platformTypeConstructor):
(_returnExpression):
* WebKitTestRunner/cocoa/TestRunnerWKWebView.mm:
(-[TestRunnerWKWebView dealloc]):
(-[TestRunnerWKWebView _stableStateOverride]):
(-[TestRunnerWKWebView _setStableStateOverride:]):
* WebKitTestRunner/ios/TestControllerIOS.mm:
(WTR::TestController::platformResetStateToConsistentValues):
* WebKitTestRunner/ios/UIScriptControllerIOS.mm:
(WTR::UIScriptController::doAsyncTask):
(WTR::UIScriptController::doAfterPresentationUpdate):
(WTR::UIScriptController::zoomToScale):
(WTR::UIScriptController::immediateScrollToOffset):
(WTR::UIScriptController::immediateZoomToScale):
(WTR::UIScriptController::stableStateOverride):
(WTR::UIScriptController::setStableStateOverride):
* WebKitTestRunner/mac/UIScriptControllerMac.mm:
(WTR::UIScriptController::doAfterPresentationUpdate):

LayoutTests:

* scrollingcoordinator/ios/non-stable-viewport-scroll-expected.txt: Added.
* scrollingcoordinator/ios/non-stable-viewport-scroll.html: Added.

git-svn-id: https://svn.webkit.org/repository/webkit/trunk@208926 268f45cc-cd09-0410-ab3c-d52691b4dbfc