Reviewed by Darin, Beth.
        
        First cut at factoring Page's UIDelegate-related functions into Chrome
        and ChromeClient.

        Layout tests pass.
        
        * bridge/mac/PageMac.mm: Removed platform-specific constructor, added
        setBridge method to replace it.
        (WebCore::Page::setBridge):

        * bridge/mac/WebCorePageBridge.h: Simplified some things based on the fact
        that WebCorePageBridge.h doesn't need to be included by ObjC-only files,
        and, now that it uses PassRefPtr, can't be.
        
        * page/Chrome.cpp: Added. Code copied and converted to c++ from WebCorePageBridge.mm.

        * page/Page.h:
        (WebCore::Page::dragCaretController): Made this function non-const so that
        m_dragCaretController doesn't have to be mutable.

WebKit:

        Reviewed by Darin, Beth.

        First cut at factoring Page's UIDelegate-related functions into Chrome
        and ChromeClient.

        Layout tests pass.
        
        * WebCoreSupport/WebEditorClient.h:
        * WebCoreSupport/WebPageBridge.mm:
        * WebKit.xcodeproj/project.pbxproj:



git-svn-id: http://svn.webkit.org/repository/webkit/trunk@17577 268f45cc-cd09-0410-ab3c-d52691b4dbfc