Introudce toCDATASection() functions, and use them.

Many DOM node classes have such cast functions.

BUG=none
TEST=none; no behavior changes.

Review URL: https://chromiumcodereview.appspot.com/23600033

git-svn-id: svn://svn.chromium.org/blink/trunk@157592 bbb929c8-8fbe-4397-9dbb-9b2b20218538
Implement Composition interface for IME API

Spec: http://www.w3.org/TR/ime-api/#composition-interface
This interface represents an ongoing IME composition. It provides attributes
representing the text being composed by an IME and its associated information.

The interface IDL is already committed at r155072.
This CL implements the interface.

BUG=238585
TEST=layouttest fast/ime

Review URL: https://chromiumcodereview.appspot.com/23604053

git-svn-id: svn://svn.chromium.org/blink/trunk@157593 bbb929c8-8fbe-4397-9dbb-9b2b20218538
NULL out the buffer in the VectorBuffer<T, 0> destructor.

This is a subset of previously reviewed CL,
https://codereview.chromium.org/23531010/ that had to be reverted due to
unknown reasons for a performance regression. Hence, relanding in pieces.

(Still chasing the Mac perf bot issue. This one-liner is a functional nop
in isolation but maybe it's not the performance nop?)

BUG=288468
R=abarth@chromium.org, tsepez@chromium.org

Review URL: https://codereview.chromium.org/23889014

git-svn-id: svn://svn.chromium.org/blink/trunk@157594 bbb929c8-8fbe-4397-9dbb-9b2b20218538