Mac: Fix renderer idle cpu usage regression.

Since polling is required only for the preferred height and mac only needs preferred width, add a flag that specifies if the client is interested in width and/or height.

This is a band-aid, the Real Fix is tracked in 44850.

BUG=44494
TEST=Open chrome's task manager. Idle renderer processes should take close to 0 %cpu instead of ~1.5 before.

Review URL: http://codereview.chromium.org/2145002

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@48056 0039d316-1c4b-4281-b951-d872f2087c98
10 files changed