Add CPU boosting hooks

 * Boost CPU to max during scrolling
 * Boost CPU to max on activity start/resume
 * Inspired by a patch from CodeAuora.

Change-Id: I72f2c2851b01fbceabddead03a4c3a7a0526ca61

Conflicts:

	services/java/com/android/server/am/ActivityStack.java

Signed-off-by: task650 <task650@gmail.com>