v8binding: Fix CSSStyleDeclaration's indexed setter not to fallback

This is a quick fix to work around an issue reported at:
https://github.com/webcompat/web-bugs/issues/25390

This patch makes readonly indexed properties not fall back to
named properties.  Coincidentally the condition only applies to
CSSStyleDeclaration, where we have the issue above.

Blink's implementation for indexed/named properties is outdated
overall.  General fix should follow.

Change-Id: I418eaf04c61ac3680ff3bc75710489b526e36100
Reviewed-on: https://chromium-review.googlesource.com/c/1460588
Commit-Queue: Hitoshi Yoshida <peria@chromium.org>
Reviewed-by: Kentaro Hara <haraken@chromium.org>
Reviewed-by: Hitoshi Yoshida <peria@chromium.org>
Cr-Commit-Position: refs/heads/master@{#630328}
1 file changed