Gardening: The following tests are flaky.

 - css3/filters/custom/composited/custom-filter-blend-modes.html
 - http/tests/local/fileapi/file-last-modified-after-delete.html

BUG=282496,283723
TBR=aboxhall@chromium.org

Review URL: https://codereview.chromium.org/23784003

git-svn-id: svn://svn.chromium.org/blink/trunk@157070 bbb929c8-8fbe-4397-9dbb-9b2b20218538
Have CSSParserContext take a Document reference in argument

Have CSSParserContext take a Document reference in argument instead of a
pointer as it can never be NULL. This avoids having to convert a reference
into a pointer at the call sites.

BUG=281400

Review URL: https://chromiumcodereview.appspot.com/23516004

git-svn-id: svn://svn.chromium.org/blink/trunk@157071 bbb929c8-8fbe-4397-9dbb-9b2b20218538
Have LinkLoader::loadLink() take a Document reference in parameter

Have LinkLoader::loadLink() take a Document reference in parameter instead
of a pointer since it can never be NULL. This avoids having to convert
a reference into a pointer at call sites.

R=tkent
BUG=281400

Review URL: https://chromiumcodereview.appspot.com/23833004

git-svn-id: svn://svn.chromium.org/blink/trunk@157072 bbb929c8-8fbe-4397-9dbb-9b2b20218538
Remove EnsurePtrConvertibleType from RefPtr assignment operators

Using of EnsurePtrConvertibleType in assignment operators (unlike copy constructors) does not help to solve ambiguousness problem.
EnsurePtrConvertibleType would make sence there if we had different assignment operators implementations selected in compile time but this is not the case.

On the other hand EnsurePtrConvertibleType affects dramatically the readability of assignment operators code so it should be removed from there.

Review URL: https://chromiumcodereview.appspot.com/23694010

git-svn-id: svn://svn.chromium.org/blink/trunk@157073 bbb929c8-8fbe-4397-9dbb-9b2b20218538
Make CSSStyleSheet.insertRule() / deleteRule() arguments mandatory

Make CSSStyleSheet.insertRule() / deleteRule() arguments mandatory to match
the specification:
http://www.w3.org/TR/DOM-Level-2-Style/css.html#CSS-CSSStyleSheet

This behavior is consistent with Firefox 23 and IE10. It is confusing what
is supposed to happen when the arguments are omitted.

BUG=

Review URL: https://chromiumcodereview.appspot.com/23530010

git-svn-id: svn://svn.chromium.org/blink/trunk@157074 bbb929c8-8fbe-4397-9dbb-9b2b20218538