Web Animations CSS: Handle transitions on unanimatable properties nicely

This patch stops us hitting an ASSERT (on creating the AnimableValue)
when we have a transition on an unanimatable property.
Note that we can't filter these out earlier as the spec[1] says:
 "unrecognized or non-animatable properties must be kept in the list"

[1] http://www.w3.org/TR/css3-transitions/#transition-property-property

BUG=303430

Review URL: https://codereview.chromium.org/39553002

git-svn-id: svn://svn.chromium.org/blink/trunk@160888 bbb929c8-8fbe-4397-9dbb-9b2b20218538
Clean up LayoutTest transitions/cancel-transition.html

R=timloh@chromium.org

Review URL: https://codereview.chromium.org/48183008

git-svn-id: svn://svn.chromium.org/blink/trunk@160889 bbb929c8-8fbe-4397-9dbb-9b2b20218538
IDL Compiler: Make [PerWorldBindings] work with [DoNotCheckSecurity]

Update the perl bindings generator so that using [PerWorldBindings] in combination
with [DoNotCheckSecurity] will actually do what the user expects.

Previously, it generated half of the necessary *ForMainWorld() static functions
and never used them.

This affects at least the generated code for the assign() and replace() operations
in Location.idl.

Kuddos to Laszlo Gombos for enabling the warnings and notifying me that we had
unused functions in the generated bindings.

R=haraken
BUG=312287

Review URL: https://codereview.chromium.org/47853004

git-svn-id: svn://svn.chromium.org/blink/trunk@160890 bbb929c8-8fbe-4397-9dbb-9b2b20218538