Reviewed by Yury Semikhatsky.

        Web Inspector: add Console API for retrieving memory stats

        Add 'console.memory' property which returns an object. Currently
        it has two fields: totalHeapSize and usedHeapSize. Later, it can be
        extended for reporting total browser's memory consumption.

        https://bugs.webkit.org/show_bug.cgi?id=39840

        * bindings/js/JSConsoleCustom.cpp:
        (WebCore::JSConsole::memory):
        * bindings/v8/custom/V8ConsoleCustom.cpp:
        (WebCore::V8Console::memoryAccessorGetter):
        * page/Console.cpp:
        (WebCore::Console::memory):
        * page/Console.h:
        * page/Console.idl:
        * fast/dom/Window/window-properties-expected.txt:
        * platform/gtk/fast/dom/Window/window-properties-expected.txt:
        * platform/qt/fast/dom/Window/window-properties-expected.txt:

git-svn-id: http://svn.webkit.org/repository/webkit/trunk@60353 268f45cc-cd09-0410-ab3c-d52691b4dbfc