Determine power hint behavior based on target activity.

Previously, logic was added surrounding whether to trigger a power
hint based on the start activity. However, this activity is not
always relevant in the calling context.

This change adjusts the logic by passing the target activity into
the method.

Fixes: 63913311
Test: press home button while on home and ensure power hint not
      triggered.

Change-Id: I71ffcae7adbc2c55ef5b2994f4c55688d0aa0ca5