[iOS WK2] WKWebView schedules nonstop layout after pressing cmb+b,i,u inside a conten...

[iOS WK2] WKWebView schedules nonstop layout after pressing cmb+b,i,u inside a contenteditable div
https://bugs.webkit.org/show_bug.cgi?id=175116
<rdar://problem/28279301>

Reviewed by Darin Adler and Ryosuke Niwa.

Source/WebCore:

WebCore support for WebPage::editorState refactoring. See WebKit ChangeLogs for more detail.

Tests: EditorStateTests.TypingAttributesBold
       EditorStateTests.TypingAttributesItalic
       EditorStateTests.TypingAttributesUnderline
       EditorStateTests.TypingAttributesTextAlignmentAbsoluteAlignmentOptions
       EditorStateTests.TypingAttributesTextAlignmentStartEnd
       EditorStateTests.TypingAttributesTextAlignmentDirectionalText
       EditorStateTests.TypingAttributesTextColor
       EditorStateTests.TypingAttributesMixedStyles
       EditorStateTests.TypingAttributesLinkColor

* css/StyleProperties.cpp:
(WebCore::StyleProperties::propertyAsColor const):
(WebCore::StyleProperties::propertyAsValueID const):

Introduces some helper functions in StyleProperties to convert CSS property values to Color or a CSSValueID.

* css/StyleProperties.h:
* editing/EditingStyle.cpp:
(WebCore::EditingStyle::hasStyle):

Pull out logic in selectionStartHasStyle that asks for a style TriState into EditingStyle::hasStyle. This is
because WebPage::editorState will now query for multiple styles at the selection start, but
selectionStartHasStyle currently recomputes styleAtSelectionStart every time it is called. To prevent extra work
from being done, we can just call selectionStartHasStyle once and use ask for EditingStyle::hasStyle on the
computed EditingStyle at selection start.

* editing/EditingStyle.h:
* editing/Editor.cpp:
(WebCore::Editor::selectionStartHasStyle const):

Source/WebKit:

Refactors WebPage::editorState to only use the StyleProperties derived from EditingStyle, instead of inserting
and removing a temporary node to figure out the style. Also adds hooks to notify the UI delegate of EditorState
changes.

* UIProcess/API/Cocoa/WKUIDelegatePrivate.h:
* UIProcess/API/Cocoa/WKWebView.mm:
(nsTextAlignment):
(dictionaryRepresentationForEditorState):
(-[WKWebView _didChangeEditorState]):

Alerts the private UI delegate of UI-side EditorState updates.

(-[WKWebView _web_editorStateDidChange]):
(-[WKWebView _executeEditCommand:argument:completion:]):
* UIProcess/API/Cocoa/WKWebViewInternal.h:
* UIProcess/API/Cocoa/WKWebViewPrivate.h:
* UIProcess/API/mac/WKView.mm:
(-[WKView _web_editorStateDidChange]):
* UIProcess/Cocoa/WebViewImpl.h:
* UIProcess/Cocoa/WebViewImpl.mm:
(WebKit::WebViewImpl::selectionDidChange):
* UIProcess/WebPageProxy.cpp:
(WebKit::WebPageProxy::executeEditCommand):

Change executeEditCommand(name, callback) to executeEditCommand(name, argument, callback) and lift out of iOS
platform code and into WebPage.cpp.

* UIProcess/WebPageProxy.h:
* UIProcess/ios/WKContentViewInteraction.mm:
(-[WKContentView executeEditCommandWithCallback:]):
(-[WKContentView _selectionChanged]):
* UIProcess/ios/WebPageProxyIOS.mm:
(WebKit::WebPageProxy::executeEditCommand): Deleted.

Move the iOS-specific implementation of executeEditCommand that invokes a callback when the web process responds
out of WebPageProxyIOS, and into cross-platform WebPageProxy code. Additionally, add a parameter for the edit
command's argument.

* WebProcess/WebPage/WebPage.cpp:
(WebKit::WebPage::editorState const):

Use EditingStyle::styleAtSelectionStart instead of Editor::styleForSelectionStart when computing an EditorState.
Tweak bold, italic and underline to use EditingStyle TriStates.

(WebKit::WebPage::executeEditCommandWithCallback):
* WebProcess/WebPage/WebPage.h:
* WebProcess/WebPage/WebPage.messages.in:
* WebProcess/WebPage/ios/WebPageIOS.mm:
(WebKit::WebPage::executeEditCommandWithCallback): Deleted.

Tools:

Introduces new testing infrastructure and API tests to test EditorState updates in the UI process. The new
EditorStateTests run on both iOS and Mac.

* TestWebKitAPI/EditingTestHarness.h: Added.
* TestWebKitAPI/EditingTestHarness.mm: Added.

EditingTestHarness is a helper object that API tests may use to apply editing commands and store EditorState
history. This test harness adds sugaring around various editing commands, and simplifies the process of checking
the state of the latest observed EditorState.

(-[EditingTestHarness initWithWebView:]):
(-[EditingTestHarness dealloc]):
(-[EditingTestHarness webView]):
(-[EditingTestHarness latestEditorState]):
(-[EditingTestHarness editorStateHistory]):
(-[EditingTestHarness insertText:andExpectEditorStateWith:]):
(-[EditingTestHarness insertHTML:andExpectEditorStateWith:]):
(-[EditingTestHarness selectAllAndExpectEditorStateWith:]):
(-[EditingTestHarness moveBackwardAndExpectEditorStateWith:]):
(-[EditingTestHarness moveWordBackwardAndExpectEditorStateWith:]):
(-[EditingTestHarness toggleBold]):
(-[EditingTestHarness toggleItalic]):
(-[EditingTestHarness toggleUnderline]):
(-[EditingTestHarness setForegroundColor:]):
(-[EditingTestHarness alignJustifiedAndExpectEditorStateWith:]):
(-[EditingTestHarness alignLeftAndExpectEditorStateWith:]):
(-[EditingTestHarness alignCenterAndExpectEditorStateWith:]):
(-[EditingTestHarness alignRightAndExpectEditorStateWith:]):
(-[EditingTestHarness insertParagraphAndExpectEditorStateWith:]):
(-[EditingTestHarness deleteBackwardAndExpectEditorStateWith:]):
(-[EditingTestHarness _execCommand:argument:expectEntries:]):

Dispatches an editing command to the web process, and blocks until a response is received. If an expected
entries dictionary is given, this will additionally verify that the latest EditorState contains all the expected
keys and values.

(-[EditingTestHarness latestEditorStateContains:]):
(-[EditingTestHarness _webView:editorStateDidChange:]):
* TestWebKitAPI/TestWebKitAPI.xcodeproj/project.pbxproj:
* TestWebKitAPI/Tests/WebKit2Cocoa/EditorStateTests.mm: Added.
(TestWebKitAPI::setUpEditorStateTestHarness):
(TestWebKitAPI::TEST):
* TestWebKitAPI/Tests/WebKit2Cocoa/editor-state-test-harness.html: Added.

LayoutTests:

* platform/ios-wk2/editing/style/unbold-in-bold-expected.txt:
* platform/mac-wk2/editing/style/unbold-in-bold-expected.txt:

Rebaseline a WK2 LayoutTest expectations. This test currently expects an empty anonymous RenderBlock to be
inserted into the render tree, but this is only a result of us adding and removing a temporary <span> when
computing a RenderStyle in WebPage::editorState -- this patch removes these empty RenderBlocks, making these
expectations' RenderTrees consistent with WebKit1.

git-svn-id: https://svn.webkit.org/repository/webkit/trunk@221065 268f45cc-cd09-0410-ab3c-d52691b4dbfc