Return 0 immediately if m_error is true in response accessors of XMLHttpRequest.

Current code is depending on the response clearing code called by abort().

Also adds layout tests to ensure spec conformance. Note that the accessor
for ArrayBuffer passes this test even without this change since abort()
clears response holders. For blob, it was returning an empty blob.

BUG=

Review URL: https://chromiumcodereview.appspot.com/17543003

git-svn-id: svn://svn.chromium.org/blink/trunk@152903 bbb929c8-8fbe-4397-9dbb-9b2b20218538
Add suppression for assert in http/tests/media/media-source/mediasource-seek-during-pending-seek.html.

BUG=252865
TBR=dpranke

Review URL: https://codereview.chromium.org/17520008

git-svn-id: svn://svn.chromium.org/blink/trunk@152904 bbb929c8-8fbe-4397-9dbb-9b2b20218538
Consistently autosize markers and layout in <ul> and <ol> lists.

This patch implements a 'global' approach where the whole list is autosized consistently and such that it remains readable after autosizing. The fix yields correct marker autosizing in cases where there are empty list items, list items containing only images and list items with form input fields.
+ Added relevant tests

BUG=248190,249386

Review URL: https://chromiumcodereview.appspot.com/17071009

git-svn-id: svn://svn.chromium.org/blink/trunk@152905 bbb929c8-8fbe-4397-9dbb-9b2b20218538