Clean up forward declarations in Source/core/frame

Clean up forward declarations in Source/core/frame

These forward references are not needed anymore. After
this patch, Source/core/frame has no unneeded forward
references anymore.

Committed: https://src.chromium.org/viewvc/blink?view=rev&revision=182357

[zhaoze.zhou, 2014-09-19 21:25:47]

zhaoze.zhou@partner.samsung.com changed reviewers:
+ rob.buis@samsung.com

[zhaoze.zhou, 2014-09-19 21:31:14]

zhaoze.zhou@partner.samsung.com changed reviewers:
+ abarth@chromium.org, haraken@chromium.org

[haraken, 2014-09-19 22:35:51]

LGTM

[zhaoze.zhou, 2014-09-19 22:36:03]

The CQ bit was checked by zhaoze.zhou@partner.samsung.com

[commit-bot: I haz the power, 2014-09-19 22:37:50]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/584273002/1

[commit-bot: I haz the power, 2014-09-19 22:45:44]

Committed patchset #1 (id:1) as 182357