Update metric names for API consistency.

The metric names need to be consistent with related APIs (e.g.
MediaCodec#getMetrics). Those APIs use dot separators rather than
slashes.

Bug 64001676

Test: Re-ran CTS, unit tests. Smoke with GPlay Movies.
Change-Id: I606e4c4bcbf630d584b9dea80471ad256764a42b
2 files changed