Remove currentView, useCurrentView properties of SVGSVGElement and SVGViewSpec interface

Intent to Deprecate and Remove:
https://groups.google.com/a/chromium.org/forum/#!topic/blink-dev/Dfqld7wjHJM

BUG=629445

Review-Url: https://codereview.chromium.org/2485113002
Cr-Commit-Position: refs/heads/master@{#431868}
23 files changed