Cleaning up task manager.
Task manager has grown to ~350 lines, and contains a mix of code dealing with tasks and with instrumenting callbacks.
This change detangles instrumentation (wrapper) from task management (buildTaskManager).
Wrapper has an extensibility mechanism that Task Manager uses to inject its own code (and state) into instrumented callbacks.
BUG=164227
TEST=No
Review URL: https://chromiumcodereview.appspot.com/22986007
git-svn-id: svn://svn.chromium.org/chrome/trunk/src@219357 0039d316-1c4b-4281-b951-d872f2087c98
3 files changed
