https://bugs.webkit.org/show_bug.cgi?id=102157
<rdar://problem/12696259>

Reviewed by Tim Horton.

Source/WebCore:

A plugin could avoid snapshotting if it started very
small (below the threshold where we autostart), and then
resized to be large (above the threshold). Detect this
case and tell the plugin to snapshot.

There unfortunately is a bit of state to track when doing
this. We have to start the snapshotting in a post-layout
task, so we carry a flag to say we're checking size but
not wanting the plugin to update (which would restart it).
We also might be a plugin that would have already restarted
due to a similar plugin being clicked or detected as dominant.
So this patch introduces a member variable that tracks what
decision has been made on snapshotting.

I also added some more logging to be more clear about what is
happening to plugins going through the snapshot process, and
changed the order of the tests in the algorithm so that domain
detection comes before examining the size.

* html/HTMLPlugInImageElement.cpp:
(WebCore::HTMLPlugInImageElement::HTMLPlugInImageElement): Initialise
    the two new member variables.
(WebCore::HTMLPlugInImageElement::setDisplayState): Mark a restarted
    plugin as NeverSnapshot. This means that if it later resizes above the
    threshold, it won't trigger the snapshot detection.
(WebCore::HTMLPlugInImageElement::checkSnapshotStatus): Renamed from
    updateSnapshotInfo. This now updates the snapshot, but also runs
    the check for size changes.
(WebCore::addPlugInsFromNodeListMatchingPlugInOrigin): Gather all plugins
    that look like a restarting plugin, not just those snapshotted. That
    way they can all be marked as NeverSnapshot.
(WebCore::HTMLPlugInImageElement::restartSimilarPlugIns): Bless every
    plugin that looks similar, whether or not it is snapshotted.
(WebCore::HTMLPlugInImageElement::userDidClickSnapshot): More logging.
(WebCore::HTMLPlugInImageElement::setIsPrimarySnapshottedPlugIn): Ditto.
(WebCore::HTMLPlugInImageElement::checkSizeChangeForSnapshotting): New
    method. If the plugin was below the threshold and is now above it,
    begin the snapshotting process.
(WebCore::HTMLPlugInImageElement::subframeLoaderWillCreatePlugIn): Plugins
    that were marked as NeverSnapshot should start immediately. Move the origin
    test earlier in the method. If a plugin avoided snapshotting due to size,
    remember the size.
(WebCore::HTMLPlugInImageElement::subframeLoaderDidCreatePlugIn): Mark the
    plugin as NeverSnapshot.

* html/HTMLPlugInImageElement.h:
(HTMLPlugInImageElement): Four new member variables:
    - the decision we made regarding snapshotting (or not), uses the SnapshotDecision enum
    - the size when it avoided snapshotting
    - a flag to indicate the post layout update was triggered due to
      a size change
(WebCore::HTMLPlugInImageElement::needsCheckForSizeChange): New method.
(WebCore::HTMLPlugInImageElement::setNeedsCheckForSizeChange): New method.
(WebCore::HTMLPlugInImageElement::snapshotDecision): Return the decision
    regarding snapshotting or not snapshotting.

* page/FrameView.cpp:
(WebCore::FrameView::addWidgetToUpdate): Guard updating the widget. We don't
    want to do it when we're checking for a size change in the plugin.
(WebCore::FrameView::updateWidget): Call new name.

* plugins/PluginViewBase.h:
(WebCore::PluginViewBase::beginSnapshottingRunningPlugin): Empty virtual
    method to snapshot a running plugin.

* rendering/RenderEmbeddedObject.cpp:
(WebCore::RenderEmbeddedObject::layout): If the plugin has increased in
    size add it to the post layout list so that it will be checked.

Source/WebKit2:

Allow a running plugin to be snapshotted. All this
means is that we start the snapshot timer again.

* WebProcess/Plugins/PluginView.cpp:
(WebKit::PluginView::beginSnapshottingRunningPlugin): Restart
    the timer.
* WebProcess/Plugins/PluginView.h: Virtual method declaration.

git-svn-id: http://svn.webkit.org/repository/webkit/trunk@148482 268f45cc-cd09-0410-ab3c-d52691b4dbfc