https://bugs.webkit.org/show_bug.cgi?id=122464
<rdar://problem/14293474>

Reviewed by Simon Fraser.

Always kickstart animated images when the page visibility changes,
which can occur via window occlusion, and which is independent of in-window
state, which we were previously using to advance animation.

No new tests; attempts to make a test have resulted only in a flaky, timing-dependent test.

* page/Frame.cpp:
(WebCore::Frame::resumeActiveDOMObjectsAndAnimations):
Move this call to resumeAnimatingImages() up to Page.

* page/FrameView.cpp:
(WebCore::FrameView::setIsInWindow):
Move this call to resumeAnimatingImages() up to Page.

* WebCore.exp.in
* page/FrameView.h:
* page/Page.h:
Move resumeAnimatingImages() itself up to Page.

* page/Page.cpp:
(WebCore::Page::setIsInWindow):
Resume animated images when we move in-window.

(WebCore::Page::setVisibilityState):
Resume animated images when we become visible.
This is the one we were previously missing.

(WebCore::Page::resumeActiveDOMObjectsAndAnimations):
Resume animated images when we're told to.

(WebCore::Page::resumeAnimatingImages):
Kickstart any animated images in all frames.


git-svn-id: http://svn.webkit.org/repository/webkit/trunk@157056 268f45cc-cd09-0410-ab3c-d52691b4dbfc