Expose WebThread rendering only when AudioWorklet flag is enabled

Expose WebThread rendering only when AudioWorklet flag enabled

The newly introduced WebThread audio rendering pipeline caused glitches
on Linux platform. To reduce the glitch and also to continue the
experiments for AudioWorklet, implement alternate render path for
WebAudio by enabling WebThread rendering only when AudioWorklet flag
is enabled.

BUG=722384
TEST=Tested the local release build with/without "--enable-blink-features=Worklet,AudioWorklet" flag.

[hongchan, 2017-05-15 17:22:40]

hongchan@chromium.org changed reviewers:
+ olka@chromium.org, rtoy@chromium.org

[hongchan, 2017-05-15 17:22:40]

PTAL.

[hongchan, 2017-05-15 17:23:22]

Description was changed from

==========
Expose WebThread rendering only when AudioWorklet flag enabled

The newly introduced WebThread audio rendering pipeline caused glitches
on Linux platform. To reduce the glitch and also to continue the
experiments for AudioWorklet, implement alternate render path for
WebAudio by enabling WebThread rendering only when AudioWorklet flag
is enabled.

BUG=722384
==========

to

==========
Expose WebThread rendering only when AudioWorklet flag enabled

The newly introduced WebThread audio rendering pipeline caused glitches
on Linux platform. To reduce the glitch and also to continue the
experiments for AudioWorklet, implement alternate render path for
WebAudio by enabling WebThread rendering only when AudioWorklet flag
is enabled.

BUG=722384
TEST=Tested the local release build with/without
"--enable-blink-features=Worklet,AudioWorklet" flag.
==========

[Raymond Toy, 2017-05-15 17:42:24]

https://codereview.chromium.org/2885483002/diff/1/third_party/WebKit/Source/p...
File third_party/WebKit/Source/platform/audio/AudioDestination.h (right):

https://codereview.chromium.org/2885483002/diff/1/third_party/WebKit/Source/p...
third_party/WebKit/Source/platform/audio/AudioDestination.h:137: // For signle
thread rendering pipe line.
"signle"

And the comment doesn't really explain what is_audio_worklet_enabled seems to
imply.  Fix the comment or the variable name.

[hongchan, 2017-05-15 20:57:32]

On 2017/05/15 17:42:24, Raymond Toy wrote:
>
https://codereview.chromium.org/2885483002/diff/1/third_party/WebKit/Source/p...
> File third_party/WebKit/Source/platform/audio/AudioDestination.h (right):
> 
>
https://codereview.chromium.org/2885483002/diff/1/third_party/WebKit/Source/p...
> third_party/WebKit/Source/platform/audio/AudioDestination.h:137: // For signle
> thread rendering pipe line.
> "signle"
> 
> And the comment doesn't really explain what is_audio_worklet_enabled seems to
> imply.  Fix the comment or the variable name.

olka@ 

FYI - this is our attempt to fix the glitches on linux platform, but we just
found out the glitches were coming from Jack installation on the machine.
I will just leave this CL here as a future reference.