Transition Between Shape Properties

The transition code checks to see if the start and end values are equal
before blending the two. The ShapeValue code must provide a more accurate
comparision to make this possible, as the previous comparision was only
based on the ShapeValue's type. Supplying a test required some minor fixup
work to animation-test-helpers, as the syntax for shapes has changed.

BUG=304916

Review URL: https://codereview.chromium.org/124363002

git-svn-id: svn://svn.chromium.org/blink/trunk@164533 bbb929c8-8fbe-4397-9dbb-9b2b20218538
[SVG] A minor clean up related to event listener attributes

onbegin, onend and onrepeat attributes are valid only for animation elements.
So, it is better for them to be in SVGSMILElement instead of SVGElement.

R=pdr@chromium.org, schenney@chromium.org, dschulze@chromium.org, fmalita@chromium.org, rob.buis@samsung.com
BUG=

Review URL: https://codereview.chromium.org/106263004

git-svn-id: svn://svn.chromium.org/blink/trunk@164534 bbb929c8-8fbe-4397-9dbb-9b2b20218538