Refactors TTS controller to content from chrome.

This is the first step in a refactor, and moves only
the TTS controller header but none of the logic, in order
to keep changes relatively small.

Refactoring the TTS controller to content is the first
step in displaying the audio icon in tabs when TTS is

BUG: 517317
Change-Id: Ic8c4c06e13001feec5c880691055ff0604127260
Reviewed-by: Dominic Mazzoni <>
Reviewed-by: John Abd-El-Malek <>
Commit-Queue: Katie Dektar <>
Cr-Commit-Position: refs/heads/master@{#611028}
43 files changed