[wrapper-tracing] Emite write barrier upon associating a wrapper

[wrapper-tracing] Emite write barrier upon associating a wrapper

Whenever we assign a reference that should be traced into V8 we need to
emit a write barrier. We automatically emit write barriers for
TraceWrapperv8Reference. However, we still use a regular (weak)
Persistent in ScriptWrappable, so we need to emit the barrier there
manually.

A follow up should convert the reference in ScriptWrappable to
TraceWrapperv8Reference.

BUG=chromium:702490
Review-Url: https://codereview.chromium.org/2759243002
Cr-Commit-Position: refs/heads/master@{#458357}
(cherry picked from commit a2011780ffefd6f9c120b80651015b3f6646244b)

Review-Url: https://codereview.chromium.org/2769773003 .
Cr-Commit-Position: refs/branch-heads/3029@{#381}
Cr-Branched-From: 939b32ee5ba05c396eef3fd992822fcca9a2e262-refs/heads/master@{#454471}
Committed: https://chromium.googlesource.com/chromium/src/+/5fe2bd0c1d820fed608f60f1e6dcda168e013bf7

[Michael Lippautz, 2017-03-23 12:28:56]

Description was changed from

==========
[wrapper-tracing] Emite write barrier upon associating a wrapper

Whenever we assign a reference that should be traced into V8 we need to
emit a write barrier. We automatically emit write barriers for
TraceWrapperv8Reference. However, we still use a regular (weak)
Persistent in ScriptWrappable, so we need to emit the barrier there
manually.

A follow up should convert the reference in ScriptWrappable to
TraceWrapperv8Reference.

BUG=chromium:702490

Review-Url: https://codereview.chromium.org/2759243002
Cr-Commit-Position: refs/heads/master@{#458357}
(cherry picked from commit a2011780ffefd6f9c120b80651015b3f6646244b)
==========

to

==========
[wrapper-tracing] Emite write barrier upon associating a wrapper

Whenever we assign a reference that should be traced into V8 we need to
emit a write barrier. We automatically emit write barriers for
TraceWrapperv8Reference. However, we still use a regular (weak)
Persistent in ScriptWrappable, so we need to emit the barrier there
manually.

A follow up should convert the reference in ScriptWrappable to
TraceWrapperv8Reference.

BUG=chromium:702490

Review-Url: https://codereview.chromium.org/2759243002
Cr-Commit-Position: refs/heads/master@{#458357}
(cherry picked from commit a2011780ffefd6f9c120b80651015b3f6646244b)

Review-Url: https://codereview.chromium.org/2769773003 .
Cr-Commit-Position: refs/branch-heads/3029@{#381}
Cr-Branched-From:
939b32ee5ba05c396eef3fd992822fcca9a2e262-refs/heads/master@{#454471}
Committed:
https://chromium.googlesource.com/chromium/src/+/5fe2bd0c1d820fed608f60f1e6dc...
==========

[Michael Lippautz, 2017-03-23 12:28:58]

Committed patchset #1 (id:1) manually as
5fe2bd0c1d820fed608f60f1e6dcda168e013bf7.