Rebaseline rtl-iframe-fixed-overflow-scrolled.html after r148290.

It has been failing consistently since it was unskipped.

TBR=haraken
BUG=

Review URL: https://codereview.chromium.org/13951015

git-svn-id: svn://svn.chromium.org/blink/trunk@148298 bbb929c8-8fbe-4397-9dbb-9b2b20218538
Remove the ENABLE_REQUEST_AUTOCOMPLETE compile-time flag.

This mostly mechanical patch should have no practical effect, as Chromium will
still hide the feature behind a runtime flag.

DOMWindow.idl was missing an EnabledAtRuntime flag on the AutocompleteErrorEvent
property; this patch addresses this deficiency.

Review URL: https://chromiumcodereview.appspot.com/13891004

git-svn-id: svn://svn.chromium.org/blink/trunk@148299 bbb929c8-8fbe-4397-9dbb-9b2b20218538
Replace WorldContextHandle with DOMWrapperWorld in Callbacks

WorldContextHandle is leaky in isolated worlds, while
RefPtr<DOMWrapperWorld> has the proper weak semantics
to allow the associated v8::Context to be freed.

A future patch will replace the uses of WorldContextHandle in
EventListeners. However, those are not leaky in the same way
as Callbacks because we manually clear all event listeners on
navigation.

R=abarth
BUG=230460

Review URL: https://codereview.chromium.org/14109007

git-svn-id: svn://svn.chromium.org/blink/trunk@148300 bbb929c8-8fbe-4397-9dbb-9b2b20218538