Activate LayerImpl tree with sync+push instead of pointer swap

This changes the activation model to do a push + sync from the pending -> active
tree instead of just doing a pointer swap.  This fixes behavior for video and
scrollbar animations and allows for recycling of the LayerImpl tree from commit
to commit.  There are several changes:

*) The tree synchronization code is templatized to support Layer->LayerImpl and
LayerImpl->LayerImpl tree syncs.  All LayerImpl subclasses now support a
createLayerImpl() call to construct a LayerImpl of matching dynamic type and a
LayerImpl::pushPropertiesTo(LayerImpl*) to sync properties.  The structural
syncing stuff is identical to the existing Layer->LayerImpl sync

*) Video layer's provider flow is tweaked.  Instead of the VideoLayerImpl being
the VideoFrameProvider::Client, a new object VideoFrameProviderClientImpl is. 
This is constructed initially on the pending tree and associated with the
VideoFrameProvider during initial commit (since that happens with the main
thread blocked).  A reference to this object is passed to the active tree, which
then registers itself for setNeedsRedraw notifications when it becomes active. 
On shutdown, the pending layer's destructor (which always happens first) unhooks
the VFPCI from the VideoFrameProvider.  This step has to happen during the
pending tree commit, not activation, since it has to happen on the impl thread
with the main thread blocked.  The active VideoLayerImpl can then proceed with a
VFPCI that isn't wired up to a VFP until the pending tree is activated, at which
point it tears down the VFPCI as well.

*) Scrollbar layer IDs are hooked up on the impl thread as well so we can set up
the pointers during LayerImpl->LayerImpl tree syncs

*) Picture layer syncing is largely unchanged, except that there's new code to
do a PictureLayerImpl -> PictureLayerImpl sync.  This step simply replaces the
active layer's pile and tilings with the pending tree's.

BUG=169143

Review URL: https://chromiumcodereview.appspot.com/11882037

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@178267 0039d316-1c4b-4281-b951-d872f2087c98

1 files changed, 2 insertions, 0 deletions

diff --git a/cc/picture_pile_impl.h b/cc/picture_pile_impl.h
index 5ca526f..c5a7b41 100644
--- a/cc/picture_pile_impl.h
+++ b/cc/picture_pile_impl.h
@@ -38,6 +38,8 @@ class CC_EXPORT PicturePileImpl : public PicturePileBase {
 
   void GatherPixelRefs(const gfx::Rect&, std::list<skia::LazyPixelRef*>&);
 
+  void PushPropertiesTo(PicturePileImpl* other);
+
   skia::RefPtr<SkPicture> GetFlattenedPicture();
 
  private: