Detect <link rel='manifest'> and notify embedder.

WebFrameClient gets a dispatchManifestChange method that will
be called by the FrameLoaderClient when the manifest
information might have changed. The embedder is not aware of
the manifest URL.

BUG=366145

Review URL: https://codereview.chromium.org/249633002

git-svn-id: svn://svn.chromium.org/blink/trunk@173664 bbb929c8-8fbe-4397-9dbb-9b2b20218538
Don't schedule invalidations when attributes changed if not needed or incorrect.

In particular, don't do it  when attributes changed if there
is no style resolver or the style change type is subtree or
greater. In both of these cases, it will either have no
additional effect or the code is incorrect.

It could be incorrect if the element was not yet attached.
It could be not needed because if there is no style resolver,
re-making it will recalc the whole document's style. Also,
style invalidation cannot trigger a style that is greater than
subtree.

Also clear style invalidation bits unconditionally in Node::detach.

BUG=366788

Review URL: https://codereview.chromium.org/273783003

git-svn-id: svn://svn.chromium.org/blink/trunk@173665 bbb929c8-8fbe-4397-9dbb-9b2b20218538
Output repaint rects for svg repaint tests

Previously all of these tests were converted to not output repaint rects
and just output pixels.  This ended up being a loss of information that
was useful to detecting missing repaints, and so they should be turned
back on where it makes sense.

BUG=369609

Review URL: https://codereview.chromium.org/262963003

git-svn-id: svn://svn.chromium.org/blink/trunk@173666 bbb929c8-8fbe-4397-9dbb-9b2b20218538
Adding a few new MSE tests based on the spec.

This is intended to make the MSE implementation more spec compliant.
More such CLs to follow after this initial round is checked in.

BUG=
TEST=new test pass

Review URL: https://codereview.chromium.org/267333006

git-svn-id: svn://svn.chromium.org/blink/trunk@173667 bbb929c8-8fbe-4397-9dbb-9b2b20218538