Retire empty source files 

Two of our C++ source files contained nothing but include directives and an empty namespace block.

BUG=

Review URL: https://chromiumcodereview.appspot.com/17477002

git-svn-id: svn://svn.chromium.org/blink/trunk@152828 bbb929c8-8fbe-4397-9dbb-9b2b20218538
Implement a more accurate Custom Element prototype 'constructor' check.

Previous document.register failed if the specified prototype had any 'constructor' own property. However the spec changed; now only non-configurable 'constructor' properties, or reusing an existing interface prototype object, causes an error.

Additionally, this configures the constructor's prototype and prototype's constructor properties correctly (per Web IDL) and adds a test for that.

I'm starting to use W3C testharness.js with a view to porting Custom Elements tests that are not Blink-specific to testharness.js and upstreaming them. Baby steps.

BUG=231461

Review URL: https://chromiumcodereview.appspot.com/17376003

git-svn-id: svn://svn.chromium.org/blink/trunk@152829 bbb929c8-8fbe-4397-9dbb-9b2b20218538
Rename ParserContentPolicy header

The header for enum ParserContentPolicy was previously named FragmentScriptingPermission.h, but with a FIXME comment and include guards for intended name ParserContentPolicy.h

BUG=

Review URL: https://chromiumcodereview.appspot.com/17465008

git-svn-id: svn://svn.chromium.org/blink/trunk@152830 bbb929c8-8fbe-4397-9dbb-9b2b20218538