GitLab

Moving the extension api dependency from TtsPlatformImplChromeOs
to TtsExtensionEngine through TtsEngineDelegate.
This is part of an effort to move TTS to content.

BUG=347045

Review URL: https://codereview.chromium.org/434083003

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@287160 0039d316-1c4b-4281-b951-d872f2087c98