Revert of Add use counters for using Attrs as Nodes. (https://codereview.chromium.org/127723002/)

Reason for revert:
Adding use counters for using Attrs as Nodes regressed dom perf and others.

BUG=335750

Original issue's description:
> Add use counters for using Attrs as Nodes.
> 
> DOM4 makes Attr no longer be a subtype of Node. This adds a use
> counter for passing Attr where Node is expected, or calling a method
> declared on Node with an Attr.
> 
> BUG=305105
> 
> Committed: https://src.chromium.org/viewvc/blink?view=rev&revision=165262

TBR=abarth@chromium.org,eseidel@chromium.org
NOTREECHECKS=true
NOTRY=true
BUG=305105

Review URL: https://codereview.chromium.org/130703003

git-svn-id: svn://svn.chromium.org/blink/trunk@165372 bbb929c8-8fbe-4397-9dbb-9b2b20218538