Fix TTS code to be compatible with new extension API parameter serialization.

Fix TTS code to be compatible with new extension API parameter serialization.

Some TTS tests broke when I landed codereview.chromium.org/10161038 because it
turned out the tts.speak method takes the incoming options dictionary argument
and re-purposes it to send an event it dispatches back to extension code. With
the above reverenced CL changes to avoid JSON.stringify, instead using
V8ValueConverter, it turns out one subtle difference between the two is that
JSON.stringify will ignore key/value pairs where the value is not a
stringifiable type (in this case, a function), whereas V8ValueConverter leaves
the key in and inserts a null value. This was causing the schema parameter
validation to fail for the event dispatch.

BUG=122675
TEST=Existing tests should pass, and re-landing the CL referenced above should
work with the TTS API browser tests.

Committed: https://src.chromium.org/viewvc/chrome?view=rev&revision=135933

[dmazzoni, 2012-05-08 19:13:15]

lgtm

[commit-bot: I haz the power, 2012-05-08 19:47:28]

CQ is trying da patch. Follow status at
https://chromium-status.appspot.com/cq/asargent@chromium.org/10382065/1

[commit-bot: I haz the power, 2012-05-08 20:08:31]

Try job failure for 10382065-1 on win_rel for step "update".
http://build.chromium.org/p/tryserver.chromium/buildstatus?builder=win_rel&nu...

Step "update" is always a major failure.
Look at the try server FAQ for more details.

[commit-bot: I haz the power, 2012-05-08 20:28:25]

CQ is trying da patch. Follow status at
https://chromium-status.appspot.com/cq/asargent@chromium.org/10382065/1

[commit-bot: I haz the power, 2012-05-08 20:48:35]

Try job failure for 10382065-1 on win_rel for step "update".
http://build.chromium.org/p/tryserver.chromium/buildstatus?builder=win_rel&nu...

Step "update" is always a major failure.
Look at the try server FAQ for more details.