Use new assertion API for process suppression on Mac
https://bugs.webkit.org/show_bug.cgi?id=111387

Patch by Kiran Muppala <cmuppala@apple.com> on 2013-03-05
Reviewed by Alexey Proskuryakov.

Source/WebKit2:

* Shared/ChildProcess.h:
(WebKit::ChildProcess::processSuppressionEnabled): Rename
m_processVisibleAssertion to m_processSuppressionAssertion.
* Shared/mac/ChildProcessMac.mm:
(WebKit::ChildProcess::setProcessSuppressionEnabled): Ditto. And,
replace calls to WKNSProcessInfoProcessAssertionWithTypes() with call to
-[NSProcessInfo beginSuspensionOfSystemBehaviors:].

WebKitLibraries:

Add WKProcessSuppressionSystemBehaviors constant for use in WebKit2 to
take a process suppression assertion.

* WebKitSystemInterface.h:

git-svn-id: http://svn.webkit.org/repository/webkit/trunk@144832 268f45cc-cd09-0410-ab3c-d52691b4dbfc