Make CompositeDataConsumerHandle non-copyable to pass compilation

Make CompositeDataConsumerHandle non-copyable to pass compilation

Without WTF_MAKE_NONCOPYABLE(CompositeDataConsumerHandle),
- Copy constructor is generated, and thus
- RefPtr<Context>'s copy constructor is required, and thus
- The definition of Context is required, but Context is forward declared.
This results in compilation error if we include CompositeDataConsumerHandle.h from modules/ (except for CompositeDataConsumerHandle.cpp and tests) on win_blink_dbg bots.

BUG=480746
Committed: https://src.chromium.org/viewvc/blink?view=rev&revision=198214

[hiroshige, 2015-07-02 13:03:11]

The CQ bit was checked by hiroshige@chromium.org to run a CQ dry run

[commit-bot: I haz the power, 2015-07-02 13:03:21]

Dry run: CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1222663002/1

[hiroshige, 2015-07-02 13:07:15]

hiroshige@chromium.org changed reviewers:
+ yhirano@chromium.org

[hiroshige, 2015-07-02 13:09:44]

PTAL.

[yhirano, 2015-07-02 13:16:34]

lgtm

[hiroshige, 2015-07-02 13:17:37]

The CQ bit was unchecked by hiroshige@chromium.org

[hiroshige, 2015-07-02 13:17:42]

The CQ bit was checked by hiroshige@chromium.org

[commit-bot: I haz the power, 2015-07-02 13:17:53]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1222663002/1

[commit-bot: I haz the power, 2015-07-02 14:16:31]

Committed patchset #1 (id:1) as
https://src.chromium.org/viewvc/blink?view=rev&revision=198214