Move MemoryNotifierAllocator to its own file, and create HeapAllocator.

Turns out that MemoryNotifierAllocator isn't going to cut it for us, because the STL heap does alignments mod 4, and the
shadow memory barfs. The new approach will be to use a HeapAllocator combined with an instance of a reporting heap
(either a WinHeap or a CtMallocHeap), and have internal STL structures use *that*.

BUG=
[email protected]

Review URL: https://codereview.appspot.com/123350045

git-svn-id: http://sawbuck.googlecode.com/svn/trunk@2263 15e8cca8-e42c-11de-a347-f34a4f72eb7d
11 files changed