[oilpan] Add missing header guard on Heap.h.

R=wibling@chromium.org
BUG=

Review URL: https://codereview.chromium.org/99623009

git-svn-id: svn://svn.chromium.org/blink/trunk@163521 bbb929c8-8fbe-4397-9dbb-9b2b20218538
Add minimal Input Method interface for WebPlugin.

supportsInputMethod() will be used to determine whether
the plugin implementation can handle input method, and
setComposition/confirmComposition corresponds to the same
method in WebViewImpl.cpp, to handle composition text
updates.

This patch is required for Chromium side patch:
https://codereview.chromium.org/103403006/

BUG=235573

Review URL: https://codereview.chromium.org/102963005

git-svn-id: svn://svn.chromium.org/blink/trunk@163522 bbb929c8-8fbe-4397-9dbb-9b2b20218538
Rename HTMLElement::form() to formOwner().

To make the correspondence to the underlying concept clearer, rename
form() as formOwner(). It intending to implement the spec's notion of
"form owner",

 http://www.whatwg.org/specs/web-apps/current-work/#form-owner

As part of this, as HTMLLegendElement.form implements its own notion
of 'form',

  http://www.whatwg.org/specs/web-apps/current-work/#dom-legend-form

a separate form() accessor has been introduced (rather
than co-opt formOwner().)

R=tkent@chromium.org
BUG=324828

Review URL: https://codereview.chromium.org/93723003

git-svn-id: svn://svn.chromium.org/blink/trunk@163523 bbb929c8-8fbe-4397-9dbb-9b2b20218538