perf: Improve performance profiles

 * Performance Profiles is going to grow into a much more powerful
   feature which can apply advanced optimizations or power saving
   techniques depending on both the state of the hardware as well
   as the current applications in use.
 * Refactor the original code and move it into PowerManager so
   that it's managed from the same place.
 * Implement "automatic performance profiles". This feature will
   automatically select a profile when specific activities are
   running. Currently this list is static and engages performance
   mode for several benchmarks (trollface).
 * Added support for a new power hint, POWER_HINT_SET_PROFILE.
   Currently, these profiles are fired using a property trigger
   in init. This is easy, but the PowerHAL can do more.
 * Moved the setting to Settings.Secure and also wrapped calls
   to the service in the DEVICE_POWER permission. Nobody should
   mess with this stuff except the system.

TODO:
 * Allow user configuration per-app.
 * Implement an advanced power-saving mode.

Change-Id: I140ebc0648c4cf05900e005923247c3180be8c93

Conflicts:
	core/java/android/provider/Settings.java
	core/res/res/values/config.xml
	core/res/res/values/symbols.xml