Implement SetWrapperReferenceFrom idl attribute within traceWrappers for media tracks

Implement SetWrapperReferenceFrom idl attribute within traceWrappers for media tracks

SetWrapperReferenceFrom(param) idl attribute denotes that when a <param> object
is alive, current object should be kept alive too. To implement the same logic
using tracing, we need to find a path from <param> object to the current object.

For the media tracks, HTMLMediaElement has to trace its track lists, and lists
have to track their elements. Audio and Video tracklists and tracks are tested
in media/avtrack/gc.html. TextTrackList, TextTrack, and VTTCue are tested in media/track/track-cue-gc-wrapper.html.

Follow status of tracing SetWrapperReferenceFrom here:

https://docs.google.com/a/google.com/spreadsheets/d/1HY7Flx2TTyWIi9S2efRWMG2nRl84E7UB2t7dx_b5K00/edit?usp=sharing

LOG=no
BUG=468240
Committed: https://crrev.com/3b6f13e00cd8cd441b8f7518f02266dc46ff4888
Cr-Commit-Position: refs/heads/master@{#393282}

[Marcel Hlopko, 2016-05-12 14:09:42]

Description was changed from

==========
Implement SetWrapperReferenceFrom idl attribute within traceWrappers for media
tracks

SetWrapperReferenceFrom(param) idl attribute denotes that when a <param> object
is alive, current object should be kept alive too. To implement the same logic
using tracing, we need to find a path from <param> object to the current object.

For the media tracks, HTMLMediaElement has to trace its track lists, and lists
have to track their elements. Audio and Video tracklists and tracks are tested
in media/avtrack/gc.html.

Follow status of tracing SetWrapperReferenceFrom here:

https://docs.google.com/a/google.com/spreadsheets/d/1HY7Flx2TTyWIi9S2efRWMG2n...

LOG=no
BUG=468240
==========

to

==========
Implement SetWrapperReferenceFrom idl attribute within traceWrappers for media
tracks

SetWrapperReferenceFrom(param) idl attribute denotes that when a <param> object
is alive, current object should be kept alive too. To implement the same logic
using tracing, we need to find a path from <param> object to the current object.

For the media tracks, HTMLMediaElement has to trace its track lists, and lists
have to track their elements. Audio and Video tracklists and tracks are tested
in media/avtrack/gc.html. TextTrackList, TextTrack, and VTTCue are tested in
media/track/track-cue-gc-wrapper.html.

Follow status of tracing SetWrapperReferenceFrom here:

https://docs.google.com/a/google.com/spreadsheets/d/1HY7Flx2TTyWIi9S2efRWMG2n...

LOG=no
BUG=468240
==========

[Marcel Hlopko, 2016-05-12 15:57:04]

hlopko@chromium.org changed reviewers:
+ haraken@chromium.org, hpayer@chromium.org, jochen@chromium.org

[Marcel Hlopko, 2016-05-12 15:57:11]

Ptal

[haraken, 2016-05-12 16:02:54]

LGTM with a comment.

https://codereview.chromium.org/1973863003/diff/20001/third_party/WebKit/Sour...
File third_party/WebKit/Source/core/html/track/TextTrack.cpp (right):

https://codereview.chromium.org/1973863003/diff/20001/third_party/WebKit/Sour...
third_party/WebKit/Source/core/html/track/TextTrack.cpp:497:
EventTargetWithInlineData::traceWrappers(visitor);

I don't think we need to trace this. EventTargetWithInlineData::traceWrappers
needs to be traced only if the object inherits from Node. Non-Node objects won't
need to call the traceWrappers().

See
https://code.google.com/p/chromium/codesearch#chromium/src/third_party/WebKit...

The same comment for other EventTargetWithInlineData::traceWrappers in this CL.

[Marcel Hlopko, 2016-05-12 16:15:51]

https://codereview.chromium.org/1973863003/diff/20001/third_party/WebKit/Sour...
File third_party/WebKit/Source/core/html/track/TextTrack.cpp (right):

https://codereview.chromium.org/1973863003/diff/20001/third_party/WebKit/Sour...
third_party/WebKit/Source/core/html/track/TextTrack.cpp:497:
EventTargetWithInlineData::traceWrappers(visitor);
You are correct. Removing. There really isn't that much to trace :)

[Marcel Hlopko, 2016-05-12 16:16:02]

The CQ bit was checked by hlopko@chromium.org

[Marcel Hlopko, 2016-05-12 16:16:02]

The patchset sent to the CQ was uploaded after l-g-t-m from haraken@chromium.org
Link to the patchset: https://codereview.chromium.org/1973863003/#ps40001
(title: "Remove unnecessary tracing")

[commit-bot: I haz the power, 2016-05-12 16:16:27]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1973863003/40001
View timeline at
 https://chromium-cq-status.appspot.com/patch-timeline/1973863003/40001

[commit-bot: I haz the power, 2016-05-12 17:29:26]

Committed patchset #3 (id:40001)

[commit-bot: I haz the power, 2016-05-12 17:31:06]

Description was changed from

==========
Implement SetWrapperReferenceFrom idl attribute within traceWrappers for media
tracks

SetWrapperReferenceFrom(param) idl attribute denotes that when a <param> object
is alive, current object should be kept alive too. To implement the same logic
using tracing, we need to find a path from <param> object to the current object.

For the media tracks, HTMLMediaElement has to trace its track lists, and lists
have to track their elements. Audio and Video tracklists and tracks are tested
in media/avtrack/gc.html. TextTrackList, TextTrack, and VTTCue are tested in
media/track/track-cue-gc-wrapper.html.

Follow status of tracing SetWrapperReferenceFrom here:

https://docs.google.com/a/google.com/spreadsheets/d/1HY7Flx2TTyWIi9S2efRWMG2n...

LOG=no
BUG=468240
==========

to

==========
Implement SetWrapperReferenceFrom idl attribute within traceWrappers for media
tracks

SetWrapperReferenceFrom(param) idl attribute denotes that when a <param> object
is alive, current object should be kept alive too. To implement the same logic
using tracing, we need to find a path from <param> object to the current object.

For the media tracks, HTMLMediaElement has to trace its track lists, and lists
have to track their elements. Audio and Video tracklists and tracks are tested
in media/avtrack/gc.html. TextTrackList, TextTrack, and VTTCue are tested in
media/track/track-cue-gc-wrapper.html.

Follow status of tracing SetWrapperReferenceFrom here:

https://docs.google.com/a/google.com/spreadsheets/d/1HY7Flx2TTyWIi9S2efRWMG2n...

LOG=no
BUG=468240

Committed: https://crrev.com/3b6f13e00cd8cd441b8f7518f02266dc46ff4888
Cr-Commit-Position: refs/heads/master@{#393282}
==========

[commit-bot: I haz the power, 2016-05-12 17:31:08]

Patchset 3 (id:??) landed as
https://crrev.com/3b6f13e00cd8cd441b8f7518f02266dc46ff4888
Cr-Commit-Position: refs/heads/master@{#393282}