Cache the boolean value in usingDelegatedRenderer.
As we are going to use this api at many places, caching the value at the first instance, will save the checking every time.

Review URL: https://codereview.chromium.org/160073005

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@251665 0039d316-1c4b-4281-b951-d872f2087c98
SVN changes up to revision 251665