AudioBufferSourceNode.start with optional parameters causes processor build-up

Starting from M42, calling ABSN.start() method with optional parameters keeps the node from getting GCed even when it is finished and its JS reference is dropped. Thus, the CPU usage keeps piling up over time.

When the node is started with optional parameters, we failed to add the node to the list of active nodes so that it never gets automatically disconnected from the graph when the node is finished.

BUG=478485
TEST=I tested it using the repro case from the bug and the CPU usage from the task manager doesn't continuously increase any more.

Committed: https://src.chromium.org/viewvc/blink?view=rev&revision=194828

[hongchan, 2015-05-01 16:54:00]

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

[hongchan, 2015-05-01 16:55:27]

PTAL.

[Raymond Toy, 2015-05-01 17:00:36]

Please fix the description: "causes the node does not get GCed"

I would also add why this was happening: We failed to add this to the list of
active nodes so that when the node is finished, it never gets automatically
disconnected from the graph.

As for TEST=, I would just say you tested it using the repro case from the bug
and the CPU usage from the task manager doesn't continuously increase any more.

https://codereview.chromium.org/1117293002/diff/1/Source/modules/webaudio/Aud...
File Source/modules/webaudio/AudioBufferSourceNode.cpp (right):

https://codereview.chromium.org/1117293002/diff/1/Source/modules/webaudio/Aud...
Source/modules/webaudio/AudioBufferSourceNode.cpp:489: // willeventually get
played even if Javascript should drop all references
Typo: "willeventually"

[Raymond Toy, 2015-05-01 17:11:32]

lgtm.

File a new bug about adding a test for this.

[hongchan, 2015-05-01 18:19:07]

The CQ bit was checked by hongchan@chromium.org

[commit-bot: I haz the power, 2015-05-01 18:19:24]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1117293002/20001

[commit-bot: I haz the power, 2015-05-01 20:13:53]

Committed patchset #2 (id:20001) as
https://src.chromium.org/viewvc/blink?view=rev&revision=194828