IDL compiler: sync Python to r167459

Python side to:
Oilpan: Move core/xml/ to oilpan's heap
https://codereview.chromium.org/166903010

BUG=239771
TBR=haraken
NOTRY=true

Review URL: https://codereview.chromium.org/176713003

git-svn-id: svn://svn.chromium.org/blink/trunk@167654 bbb929c8-8fbe-4397-9dbb-9b2b20218538
IDL compiler: [ImplementedAs] in [SetWrapperReferenceTo]

* use cpp_type instead of hard-coded raw pointer
* also fix test cases so TestObject/TestObjectPython has *no* extended
  attributes on the interface (those go on TestInterface)

BUG=239771
TBR=haraken
NOTRY=true

Review URL: https://codereview.chromium.org/176873002

git-svn-id: svn://svn.chromium.org/blink/trunk@167655 bbb929c8-8fbe-4397-9dbb-9b2b20218538
SVGPathSegList was missing SetWrapperReference call to contextElement.

This caused the contextElement to be gc-ed while its tearoffs are active, leading to use-after-free.

BUG=308818
BUG=346110

Review URL: https://codereview.chromium.org/176683002

git-svn-id: svn://svn.chromium.org/blink/trunk@167656 bbb929c8-8fbe-4397-9dbb-9b2b20218538
Add WebDocument::focusedElement.

WebDocument::focusedNode should be focusedElement.
DOM, HTML, SVG specifications assume only elements can be focused.
Blink exposes focusedNode api and returns WebNode casting from Element*.
This change would make a cleaner API and expose focused
WebElement which is more rich than WebNode.

BUG=258763

Review URL: https://codereview.chromium.org/173283003

git-svn-id: svn://svn.chromium.org/blink/trunk@167657 bbb929c8-8fbe-4397-9dbb-9b2b20218538