Reviewed by Darin Adler.

        - <rdar://problem/6234307> Support action methods for setting and clearing character-level directionality
        - WebCore part of <rdar://problem/6234337> Add a Text Direction menu to the default context menu when appropriate

        * WebCore.base.exp: Exported
        WebCore::Settings::setTextDirectionSubmenuInclusionBehavior().

        * editing/ApplyStyleCommand.cpp:
        (StyleChange::init): Changed to always include the direction property
        in the result if the unicode-bidi property is included.
        (ApplyStyleCommand::splitAncestorsWithUnicodeBidi): Added. Finds the
        highest ancestor of the given node that establishes bidi embedding. If
        that embedding agrees with the given allowed direction, finds the
        second-highest embedding ancestor. Splits all nodes through that
        ancestor. If the highest embedding ancestor did not need to be split,
        it is returned.
        (ApplyStyleCommand::removeEmbeddingUpToEnclosingBlock): Added. Removes
        bidi embedding attributes and styles from all ancestors of the given
        node up to its enclosing block or the given node.
        (ApplyStyleCommand::applyInlineStyle): Added code to handle the
        unicode-bidi property. Applying style the includes this property
        involves removing all bidi embedding in effect, except  for one-level
        embedding that agrees with the desired embedding, then applying the
        desired embedding where it is not already in effect.
        (ApplyStyleCommand::applyInlineStyleToRange): Factored out from
        applyInlineStyle().
        (ApplyStyleCommand::removeHTMLBidiEmbeddingStyle): Added. Removed the
        "dir" attribute if necessary and the element if it becomes an unstyled
        style span.
        (ApplyStyleCommand::removeCSSStyle): Changed to remove the direction
        property when removing the unicode-bidi property.
        (ApplyStyleCommand::removeInlineStyle): Added a call to
        removeHTMLBidiEmbeddingStyle().

        * editing/ApplyStyleCommand.h:
        * editing/Editor.cpp:
        (Editor::textDirectionForSelection): Added. Returns the character-level
        writing direction of the selection if it is uniform and simple (at most
        one level of embedding).
        (Editor::hasBidiSelection): Added. Returns true if the selection lies
        entirely within a single block, and that block has direction:rtl or
        contains any inline boxes with non-zero bidi embedding level.

        * editing/Editor.h:
        * editing/EditorCommand.cpp:
        (stateTextWritingDirection): Added this helper function for deciding
        the state of Text Direction submenu items.
        (executeMakeTextWritingDirectionLeftToRight): Added. Applies
        "unicode-bidi: embed; direction: ltr;".
        (executeMakeTextWritingDirectionNatural): Added. Applies
        "unicode-bidi: normal;"
        (executeMakeTextWritingDirectionRightToLeft): Added. Applies
        "unicode-bidi: embed; direction: rtl;".
        (stateTextWritingDirectionLeftToRight): Added.
        (stateTextWritingDirectionNatural): Added.
        (stateTextWritingDirectionRightToLeft): Added.
        (createCommandMap): Added "MakeTextWritingDirectionLeftToRight",
        "MakeTextWritingDirectionNatural",
        and "MakeTextWritingDirectionRightToLeft".

        * editing/InsertTextCommand.cpp:
        (InsertTextCommand::input): Added code to maintain the unicode-bidi
        and direction properties in the typing style. Even if they have the
        same values as the computed style at the caret, they need to be included
        in the typing style so that inserted text will not inherit any nested
        embedding.

        * page/ContextMenuController.cpp:
        (ContextMenuController::contextMenuItemSelected): Added calls to
        the editor for the text direction menu items.

        * page/Frame.cpp
        (Frame::computeAndSetTypingStyle): Added code to maintain the
        unicode-bidi and direction properties in the typing style.

        * page/Settings.cpp:
        (Settings::setTextDirectionSubmenuInclusionBehavior): Added this setter.

        * page/Settings.h: Added a TextDirectionSubmenuInclusionBehavior enum,
        an m_textDirectionSubmenuInclusionBehavior member, and accessors.

        * page/mac/WebCoreViewFactory.h:
        * platform/ContextMenu.cpp:
        (WebCore::createAndAppendTextDirectionSubMenu): Added.
        (ContextMenu::populate): Added the Text Direction submenu item based on
        the inclusion behavior and the existence of a bidi selection.
        (ContextMenu::checkOrEnableIfNeeded): Added code for the text direction
        menu items.

        * platform/ContextMenuItem.h:
        * platform/LocalizedStrings.h: Declared
        contextMenuItemTagTextDirectionMenu().

        * platform/mac/LocalizedStringsMac.mm: Defined
        contextMenuItemTagTextDirectionMenu().

        * rendering/RenderBlock.cpp:
        (RenderBlock::containsNonZeroBidiLevel): Added.
        * rendering/RenderBlock.h:

WebKit:

        Reviewed by Darin Adler.

        - part of <rdar://problem/6234337> Add a Text Direction menu to the default context menu when appropriate

        * English.lproj/Localizable.strings: Added the Text Direction submenu
        title.

WebKit/mac:

        Reviewed by Darin Adler.

        - <rdar://problem/6234333> Implement action methods for setting and clearing character-level directionality
        - part of <rdar://problem/6234337> Add a Text Direction menu to the default context menu when appropriate

        * WebCoreSupport/WebViewFactory.mm:
        (-[WebViewFactory contextMenuItemTagTextDirectionMenu]): Added.
        * WebView/WebFrame.mm:
        (core): Added a convertor from WebTextDirectionSubmenuInclusionBehavior
        to WebCore::TextDirectionSubmenuInclusionBehavior.
        * WebView/WebFrameInternal.h:
        * WebView/WebHTMLView.mm:
        Added makeTextWritingDirectionLeftToRight:,
        makeTextWritingDirectionNatural: and
        makeTextWritingDirectionRightToLeft: using the WEBCORE_COMMAND macro.
        * WebView/WebPreferenceKeysPrivate.h:
        Added WebKitTextDirectionSubmenuInclusionBehaviorPreferenceKey.
        * WebView/WebPreferences.mm:
        (+[WebPreferences initialize]): Set the default Text Direction
        submenu inclusion behavior to never include.
        (-[WebPreferences textDirectionSubmenuInclusionBehavior]): Added this
        accessor.
        (-[WebPreferences setTextDirectionSubmenuInclusionBehavior:]): Ditto.
        * WebView/WebPreferencesPrivate.h: Defined the
        WebTextDirectionSubmenuInclusionBehavior enum and declared
        accessors.
        * WebView/WebUIDelegatePrivate.h:
        * WebView/WebView.mm:
        (-[WebView _preferencesChangedNotification:]): Added code to transfer
        the Text Direction submenu inclusion behavior preference to WebCore
        settings.



git-svn-id: http://svn.webkit.org/repository/webkit/trunk@38410 268f45cc-cd09-0410-ab3c-d52691b4dbfc