Revert of IDL: Null values should be converted for non-nullable dictionary members

Revert of IDL: Null values should be converted for non-nullable dictionary members (patchset #2 id:20001 of https://codereview.chromium.org/765673005/)

Reason for revert:
Build failed: http://build.chromium.org/p/chromium.webkit/builders/Linux%20GN/builds/13713/steps/compile/logs/stdio

Original issue's description:
> IDL: Null values should be converted for non-nullable dictionary members
> 
> The current implementation of the binding layer treats null values
> as the same as undefined, but this behavior doesn't match what the
> spec specified. According to the spec[1], when null is passed to
> a dictionary member, we should do conversion unless the member is
> nullable. For example, given a dictionary member and the type
> of the member is DOMString, passing null should result in "null"
> (of type string). This CL changes the binding's behavior to follow
> the spec.
> 
> [1] http://heycam.github.io/webidl/#es-dictionary
> BUG=321462
> 
> Committed: https://src.chromium.org/viewvc/blink?view=rev&revision=186169

TBR=haraken@chromium.org,jl@opera.com,jinho.bang@samsung.com,bashi@chromium.org
NOTREECHECKS=true
NOTRY=true
BUG=321462
Committed: https://src.chromium.org/viewvc/blink?view=rev&revision=186170

[pfeldman, 2014-11-28 11:45:46]

Created Revert of IDL: Null values should be converted for non-nullable
dictionary members

[commit-bot: I haz the power, 2014-11-28 11:46:32]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/768793002/1

[commit-bot: I haz the power, 2014-11-28 11:47:10]

Committed patchset #1 (id:1) as
https://src.chromium.org/viewvc/blink?view=rev&revision=186170

[haraken, 2014-11-28 11:47:32]

LGTM, thanks for the revert!