bindings: Stop using the given creationContext in public APIs.

bindings: Stop using the given creationContext in public APIs.

The creation context passed through the public APIs may be unsafe
and faked by user script.  The callers of the APIs often do not
check if the context is safe and valid or not.  Plus, there shouldn't
be a case that a caller needs to handle cross-origin cases, so let us
always use the current context instead of the creation context given
through the callers, which are not reliable.

BUG=497507
Committed: https://src.chromium.org/viewvc/blink?view=rev&revision=196755

[Yuki, 2015-06-08 10:35:09]

yukishiino@chromium.org changed reviewers:
+ haraken@chromium.org

[Yuki, 2015-06-08 10:35:10]

Could you review this CL?

I'm now running browser_tests locally.

[haraken, 2015-06-08 10:55:51]

LGTM. It is nasty to ignore the passed-in creationContext and use the current
context instead, but I think this gives us a correct behavior in almost all
cases in practice. (At the very least, it is much more correct than trusting the
passed-in creationContext, as explained in the bug.)

In a follow-up, we might want to:

1) Add ASSERT(isolate->GetCurrentContext() == creationContext).

2) Fix all call sites that hit the ASSERT.

[Yuki, 2015-06-09 10:03:55]

The CQ bit was checked by yukishiino@chromium.org

[commit-bot: I haz the power, 2015-06-09 10:04:18]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1166793006/1

[commit-bot: I haz the power, 2015-06-09 11:34:26]

Committed patchset #1 (id:1) as
https://src.chromium.org/viewvc/blink?view=rev&revision=196755