Revert 157076 "Allow context-less document dispatching events."

Caused crashes of WebGL context lost conformance tests.

> Allow context-less document dispatching events.
> 
> This change allows context-less documents like ones from XHR to
> dispatch events. More precicely, it allows event listeners in these documents
> to react dispatched events.
> 
> For that purpose, it introduces Document::m_contextDocument
> which points the document of the context where the document is created.
> 
> To prevent inline event handlers on context-less documents from being fired,
> the change extracts the eligibility check from V8LazyEventLitener
> to Document::allowInlineEventHandlers() and tightens it, so that it says no
> if the owner document of the event-holding node doesn't have context (=Frame).
> 
> BUG=275285
> TEST=event-on-created-document.html, event-on-xhr-document.html, import-events.html,
>      sub-imports-onload.html
> R=abarth@chromium.org, dglazkov@chromium.org, esprehn@chromium.org
> 
> Review URL: https://chromiumcodereview.appspot.com/23330004

TBR=morrita@chromium.org
BUG=285357,275285

Review URL: https://codereview.chromium.org/23627006

git-svn-id: svn://svn.chromium.org/blink/trunk@157241 bbb929c8-8fbe-4397-9dbb-9b2b20218538
Make Pasteboard deal with ChromiumDataObject instead of Clipboard.

ChromiumDataObject is a platform class; Clipboard is a DOM class.
This works towards removing the layering violation caused by Pasteboard
knowing too much about the DOM.

BUG=276565

Review URL: https://chromiumcodereview.appspot.com/22929033

git-svn-id: svn://svn.chromium.org/blink/trunk@157242 bbb929c8-8fbe-4397-9dbb-9b2b20218538
Fix threading races on ConvolverNode::m_reverb in ConvolverNode::tailTime()

According to the crash report (https://cluster-fuzz.appspot.com/testcase?key=6515787040817152),
ConvolverNode::m_reverb races between ConvolverNode::tailTime() and ConvolverNode::setBuffer().
This CL adds a proper lock for ConvolverNode::m_reverb.

BUG=284785
No tests because the crash depends on threading races and thus not reproducible.

Review URL: https://chromiumcodereview.appspot.com/23926002

git-svn-id: svn://svn.chromium.org/blink/trunk@157243 bbb929c8-8fbe-4397-9dbb-9b2b20218538
Switch non-gdi windows font path to use new SkFontMgr

Switch the Skia font rendering codepath (which is not on by default)
to use the new SkFontMgr class for typeface construction.

BUG=249099
R=reed@google.com

Review URL: https://chromiumcodereview.appspot.com/23480016

git-svn-id: svn://svn.chromium.org/blink/trunk@157244 bbb929c8-8fbe-4397-9dbb-9b2b20218538
Fix threading races on ConvolverNode::m_reverb in ConvolverNode::latencyFrames()

According to the crash report (https://cluster-fuzz.appspot.com/testcase?key=6515787040817152),
ConvolverNode::m_reverb races between ConvolverNode::latencyFrames() and ConvolverNode::setBuffer().
This CL adds a proper lock for ConvolverNode::m_reverb.

BUG=223962
No tests because the crash depends on threading races and thus not reproducible.

Review URL: https://chromiumcodereview.appspot.com/23514037

git-svn-id: svn://svn.chromium.org/blink/trunk@157245 bbb929c8-8fbe-4397-9dbb-9b2b20218538