Allow Blink embedder to decide FileSystem API permission asynchronously

This is the first of several patches to switch over the FileSystem API to be asynchronous. This CL is essentially a NOOP. It introduces the appropriate plumbing to the Blink embedder to allow an asynchronous permission check.

BUG=343382

Review URL: https://codereview.chromium.org/177003022

git-svn-id: svn://svn.chromium.org/blink/trunk@168840 bbb929c8-8fbe-4397-9dbb-9b2b20218538
Change BreakingContext to use right dir for width

BreakingContext::handleText currently uses the unicode direction from
the BidiResolver. This works fine for characters with strong
directionality but fails for all other directionalities as the dir
value has not yet been resolved (by the UBA).
Instead change it to use the version of constructTextRun that
resolved the directionality from the text content.

TEST=fast/text/international/rtl-text-wrapping.html
BUG=348554
R=dglazkov@chromium.org

Review URL: https://codereview.chromium.org/190623003

git-svn-id: svn://svn.chromium.org/blink/trunk@168841 bbb929c8-8fbe-4397-9dbb-9b2b20218538
Rename Path to Path2D

This change affects Path and CanvasRenderingContext2D which has some methods which path Path arguments.

Path, and after it's renamed Path2D, and the methods on CanvasRenderingContext2D that take Path/Path2D arguments are hidden behind the --enable-experimental-canvas-features flag and will remain hidden behind that flag.

Agreement to rename Path to Path2D:
  http://lists.w3.org/Archives/Public/public-whatwg-archive/2013Nov/0204.html

Spec reference:  
  None, the spec will be updated to Path2D after the rename.

Intent to Implement isn't needed:
  https://groups.google.com/a/chromium.org/d/msg/blink-dev/5l-nySXWkqA/62572JTekPcJ

BUG=347128

Review URL: https://codereview.chromium.org/178673002

git-svn-id: svn://svn.chromium.org/blink/trunk@168842 bbb929c8-8fbe-4397-9dbb-9b2b20218538
Use new is*Element() helper functions in accessibility code

Use new is*Element() helpers in accessibility code. This makes the code clearer
and simpler. Also use the new Traversal<*Element> API where suitable.

R=eseidel, adamk
BUG=346095

Review URL: https://codereview.chromium.org/192413002

git-svn-id: svn://svn.chromium.org/blink/trunk@168843 bbb929c8-8fbe-4397-9dbb-9b2b20218538