Remove unused UseCounter features

These are the bugs in which the enum values became unused:

LegacyNotifications/LegacyTextNotifications:
https://code.google.com/p/chromium/issues/detail?id=348019

LegacyWebAudio/WebAudioStart:
https://code.google.com/p/chromium/issues/detail?id=358398

PrefixedShadowRootConstructor:
https://code.google.com/p/chromium/issues/detail?id=242153

SVGAnimateColorElement:
https://code.google.com/p/chromium/issues/detail?id=332839

PrefixedMediaSourceOpen:
https://code.google.com/p/chromium/issues/detail?id=363444

JavascriptExhaustedMemory:
https://code.google.com/p/chromium/issues/detail?id=347724

BUG=none

Review URL: https://codereview.chromium.org/263503002

git-svn-id: svn://svn.chromium.org/blink/trunk@172937 bbb929c8-8fbe-4397-9dbb-9b2b20218538
[CSS Shapes] complex calc args for inset round vanish

In order to use calc in the rounded parameters for inset shapes, we need to pass RenderStyle for the value creation as we did for the width arguments.
Without taking RenderStyle into account, we hit an assert not reached in CSSPrimitiveValue::init in the debug builds.

This is a merge of http://trac.webkit.org/changeset/167936 by Zoltan Horvath <zoltan@webkit.org>.

BUG=367889

Review URL: https://codereview.chromium.org/255193002

git-svn-id: svn://svn.chromium.org/blink/trunk@172938 bbb929c8-8fbe-4397-9dbb-9b2b20218538