Rename GetHeapType to GetHeapFeatures, and add optional IsAllocated function.

This adds support for an optionally implemented ability to query a heap if it has made the given allocation. The HeapManager will require this when recovering from a corrupted BlockTrailer.

BUG=
R=sebmarchand@chromium.org

Review URL: https://codereview.appspot.com/114570043

git-svn-id: http://sawbuck.googlecode.com/svn/trunk@2213 15e8cca8-e42c-11de-a347-f34a4f72eb7d
13 files changed