Make WTF::IsGarbageCollectedType<> work for GC mixin instances.

Make WTF::IsGarbageCollectedType<> work for GC mixin instances.

The trick that IsGarbageCollectedType<T> uses of probing for the presence
of a "marker" type name within T to detect if T derives from a GC base
or is another kind of heap object, doesn't work for GC mixins.

For instance,

 class Mixin : public GarbageCollectedMixin { ... };
 class Use : public GarbageCollected<Use>, public Mixin {
     USING_GARBAGE_COLLECTED_MIXIN(Use);
     ...
 };

As both GarbageCollected<> and GarbageCollectedMixin<> provide the marker
type name, referring to the marker type name is ambiguous when attempted
over Use. Address the problem by overriding and defining the marker for
mixin instances also.

R=haraken
BUG=

Committed: https://crrev.com/c3930ed530f6384d08ee0dcf4df33d911ae506ac
Cr-Commit-Position: refs/heads/master@{#384851}

[sof, 2016-04-03 20:15:54]

sigbjornf@opera.com changed reviewers:
+ oilpan-reviews@chromium.org

[sof, 2016-04-03 20:15:55]

please take a look.

I wonder how this one has gone undetected.

[haraken, 2016-04-03 23:37:13]

LGTM

[sof, 2016-04-04 05:06:40]

Description was changed from

==========
Make WTF::IsGarbageCollectedType<> work for GC mixin instances.

The trick that IsGarbageCollectedType<T> uses of probing for the presence
of a "marker" type name within T to detect if T derives from a GC base
or is another kind of heap object, doesn't work for GC mixins.

For instance,

 class Mixin : public GarbageCollectedMixin { ... };
 class Use : public GarbageCollected<Use>, public Mixin {
     USING_GARBAGE_COLLECTED_MIXIN(Use);
     ...
 };

As both GarbageCollected<> and GarbageCollectedMixin<> provide the marker
type name, referring to the marker type name is ambiguous when attempted
over Use. Address the problem by overriding and defining the marker for
mixin instances also.

R=
BUG=
==========

to

==========
Make WTF::IsGarbageCollectedType<> work for GC mixin instances.

The trick that IsGarbageCollectedType<T> uses of probing for the presence
of a "marker" type name within T to detect if T derives from a GC base
or is another kind of heap object, doesn't work for GC mixins.

For instance,

 class Mixin : public GarbageCollectedMixin { ... };
 class Use : public GarbageCollected<Use>, public Mixin {
     USING_GARBAGE_COLLECTED_MIXIN(Use);
     ...
 };

As both GarbageCollected<> and GarbageCollectedMixin<> provide the marker
type name, referring to the marker type name is ambiguous when attempted
over Use. Address the problem by overriding and defining the marker for
mixin instances also.

R=haraken
BUG=
==========

[sof, 2016-04-04 05:06:48]

The CQ bit was checked by sigbjornf@opera.com

[commit-bot: I haz the power, 2016-04-04 05:06:55]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1851383002/1
View timeline at
 https://chromium-cq-status.appspot.com/patch-timeline/1851383002/1

[commit-bot: I haz the power, 2016-04-04 06:02:15]

Description was changed from

==========
Make WTF::IsGarbageCollectedType<> work for GC mixin instances.

The trick that IsGarbageCollectedType<T> uses of probing for the presence
of a "marker" type name within T to detect if T derives from a GC base
or is another kind of heap object, doesn't work for GC mixins.

For instance,

 class Mixin : public GarbageCollectedMixin { ... };
 class Use : public GarbageCollected<Use>, public Mixin {
     USING_GARBAGE_COLLECTED_MIXIN(Use);
     ...
 };

As both GarbageCollected<> and GarbageCollectedMixin<> provide the marker
type name, referring to the marker type name is ambiguous when attempted
over Use. Address the problem by overriding and defining the marker for
mixin instances also.

R=haraken
BUG=
==========

to

==========
Make WTF::IsGarbageCollectedType<> work for GC mixin instances.

The trick that IsGarbageCollectedType<T> uses of probing for the presence
of a "marker" type name within T to detect if T derives from a GC base
or is another kind of heap object, doesn't work for GC mixins.

For instance,

 class Mixin : public GarbageCollectedMixin { ... };
 class Use : public GarbageCollected<Use>, public Mixin {
     USING_GARBAGE_COLLECTED_MIXIN(Use);
     ...
 };

As both GarbageCollected<> and GarbageCollectedMixin<> provide the marker
type name, referring to the marker type name is ambiguous when attempted
over Use. Address the problem by overriding and defining the marker for
mixin instances also.

R=haraken
BUG=
==========

[commit-bot: I haz the power, 2016-04-04 06:02:16]

Committed patchset #1 (id:1)

[commit-bot: I haz the power, 2016-04-04 06:03:31]

Description was changed from

==========
Make WTF::IsGarbageCollectedType<> work for GC mixin instances.

The trick that IsGarbageCollectedType<T> uses of probing for the presence
of a "marker" type name within T to detect if T derives from a GC base
or is another kind of heap object, doesn't work for GC mixins.

For instance,

 class Mixin : public GarbageCollectedMixin { ... };
 class Use : public GarbageCollected<Use>, public Mixin {
     USING_GARBAGE_COLLECTED_MIXIN(Use);
     ...
 };

As both GarbageCollected<> and GarbageCollectedMixin<> provide the marker
type name, referring to the marker type name is ambiguous when attempted
over Use. Address the problem by overriding and defining the marker for
mixin instances also.

R=haraken
BUG=
==========

to

==========
Make WTF::IsGarbageCollectedType<> work for GC mixin instances.

The trick that IsGarbageCollectedType<T> uses of probing for the presence
of a "marker" type name within T to detect if T derives from a GC base
or is another kind of heap object, doesn't work for GC mixins.

For instance,

 class Mixin : public GarbageCollectedMixin { ... };
 class Use : public GarbageCollected<Use>, public Mixin {
     USING_GARBAGE_COLLECTED_MIXIN(Use);
     ...
 };

As both GarbageCollected<> and GarbageCollectedMixin<> provide the marker
type name, referring to the marker type name is ambiguous when attempted
over Use. Address the problem by overriding and defining the marker for
mixin instances also.

R=haraken
BUG=

Committed: https://crrev.com/c3930ed530f6384d08ee0dcf4df33d911ae506ac
Cr-Commit-Position: refs/heads/master@{#384851}
==========

[commit-bot: I haz the power, 2016-04-04 06:03:32]

Patchset 1 (id:??) landed as
https://crrev.com/c3930ed530f6384d08ee0dcf4df33d911ae506ac
Cr-Commit-Position: refs/heads/master@{#384851}