[Chromium] add option for 2d canvas defered rendering to DumpRenderTree

[Chromium] add option for 2d canvas defered rendering to DumpRenderTree
https://bugs.webkit.org/show_bug.cgi?id=78039

Patch by Justin Novosad <junov@chromium.org> on 2012-02-07
Reviewed by Stephen White.

Adding the --enable-deferred-2d-canvas switch to DumpRenderTree

* DumpRenderTree/chromium/DumpRenderTree.cpp:
(main):
* DumpRenderTree/chromium/TestShell.cpp:
(TestShell::TestShell):
(TestShell::resetWebSettings):
(TestShell::runFileTest):
* DumpRenderTree/chromium/TestShell.h:
(TestShell::setDeferred2dCanvasEnabled):
(TestShell):
* DumpRenderTree/chromium/WebPreferences.cpp:
(WebPreferences::reset):
(WebPreferences::applyTo):
* DumpRenderTree/chromium/WebPreferences.h:
(WebPreferences):

git-svn-id: http://svn.webkit.org/repository/webkit/trunk@107022 268f45cc-cd09-0410-ab3c-d52691b4dbfc