Do not always request a new commit when memory limit is changed.
Skip re-committing if there is already enough memory to for everything,
and the new memory limit hasn't changed that situation.
In situations where fluctuations in, say, WebGL's memory usage causes
the page's limit to move up and down frequently, this will prevent extra
commits unless the changes actually change what is being rendered.
Add tests for new LTH and PRM functions.
BUG=189199
Review URL: https://chromiumcodereview.appspot.com/12958007
git-svn-id: svn://svn.chromium.org/chrome/trunk/src@191252 0039d316-1c4b-4281-b951-d872f2087c98
7 files changed
