Add PipelineStatus UMA logging to media_internals
Listen for media_log events and save every players state in a map indexed by renderer_id.
When a tab is closed, all players corresponding to the renderer will be logged to UMA.

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Review URL: https://codereview.chromium.org/697463005

Cr-Commit-Position: refs/heads/master@{#303973}
5 files changed