Complete HTMLConstructor algorithm, based off Issue#2386563002 by davaajav.

Depends on Issue#2419383002.

Completed HTMLConstructor algorithm, modified custom element definition algorithm
    /bindings/core/v8/V8HTMLConstructor.cpp
    /core/dom/custom/CustomElementRegistry.cpp

Added HTMLConstructor extended attribute to HTML element IDLS:
    HTMLDivElement.idl
    HTMLParagraphElement.idl

Created separate class for HTMLConstructor
    /bindings/bindings.gni
    /bindings/core/v8/V8HTMLConstructor.cpp
    /bindings/core/v8/V8HTMLConstructor.h
    /bindings/scripts/v8_interface.py
    /bindings/templates/interface.cpp.tmpl
    /bindings/templates/interface.h.tmpl

Updated custom-elements tests and expected results.

The changes should allow Layout test imported/wpt/custom-elements/htmlconstructor/newtarget.html to pass, but it's buggy.
Bug fix for test here: https://github.com/w3c/web-platform-tests/commit/ac12d9a15df23cf25cbfb904902dad2bd6dfdf6a

BUG=648828

Review-Url: https://codereview.chromium.org/2424693002
Cr-Commit-Position: refs/heads/master@{#428286}
14 files changed