[blimp] Add SkPicture caching support.

cc/layers/picture_layer.cc

Index: cc/layers/picture_layer.cc
diff --git a/cc/layers/picture_layer.cc b/cc/layers/picture_layer.cc
index 526c7a498e72a2b52e3eb70014116f7cd66fa74f..c18dc5931080a2322a997b55050919b5b4b3eee3 100644
--- a/cc/layers/picture_layer.cc
+++ b/cc/layers/picture_layer.cc
@@ -37,6 +37,9 @@ PictureLayer::PictureLayer(ContentLayerClient* client,
 }
 
 PictureLayer::~PictureLayer() {
+  // If there is a RecordingSource, it needs to be unregistered.
+  if (recording_source_)
+    recording_source_->MarkForUnregistration();
 }
 
 std::unique_ptr<LayerImpl> PictureLayer::CreateLayerImpl(
@@ -66,12 +69,37 @@ void PictureLayer::PushPropertiesTo(LayerImpl* base_layer) {
 }
 
 void PictureLayer::SetLayerTreeHost(LayerTreeHost* host) {
+  LayerTreeHost* old_host = layer_tree_host();
   Layer::SetLayerTreeHost(host);
+  if (old_host == host)

[vmpstr, 2016/06/01 00:10:56]

When does this happen? Should this check be even higher?

[nyquist, 2016/06/04 00:24:57]

Removed now.

+    return;
+
+  if (old_host && recording_source_) {
+    // The LayerTreeHost has changed and there was already a recording source,
+    // so unregister everything in the RecordingSource.
+    recording_source_->MarkForUnregistration();

[vmpstr, 2016/06/01 00:10:56]

This feels wrong. 

[nyquist, 2016/06/04 00:24:57]

Removed this block.

+    recording_source_->set_engine_picture_cache(nullptr);
+    recording_source_->set_client_picture_cache(nullptr);
+  }
+
   if (!host)
     return;
 
   if (!recording_source_)
     recording_source_.reset(new RecordingSource);

[vmpstr, 2016/06/01 00:10:56]

This makes me believe that we can just do the Unmarking in the recording source
dtor. 

[nyquist, 2016/06/04 00:24:57]

Done.

+
+  // Ensure the recording source has a pointer to the  correct picture cache.
+  if (layer_tree_host()->IsRemoteServer()) {
+    recording_source_->set_engine_picture_cache(

[vmpstr, 2016/06/01 00:10:57]

likewise, we can mark things in the set function? Ie unmark the old cache (if it
was there) and mark the new cache (if it exists)

[nyquist, 2016/06/04 00:24:57]

Done.

+        layer_tree_host()->engine_picture_cache());
+  }
+  if (layer_tree_host()->IsRemoteClient()) {
+    recording_source_->set_client_picture_cache(
+        layer_tree_host()->client_picture_cache());
+  }
+  // Ensure that the currently empty RecordingSource is set in the marked state.
+  recording_source_->MarkForRegistration();
+
   recording_source_->SetSlowdownRasterScaleFactor(
       host->debug_state().slow_down_raster_scale_factor);
   // If we need to enable image decode tasks, then we have to generate the
@@ -179,9 +207,8 @@ void PictureLayer::LayerSpecificPropertiesToProto(
   DropRecordingSourceContentIfInvalid();
 
   proto::PictureLayerProperties* picture = proto->mutable_picture();
-  recording_source_->ToProtobuf(
-      picture->mutable_recording_source(),
-      layer_tree_host()->image_serialization_processor());
+  recording_source_->ToProtobuf(picture->mutable_recording_source());
+
   RegionToProto(last_updated_invalidation_, picture->mutable_invalidation());
   picture->set_is_mask(is_mask_);
   picture->set_nearest_neighbor(nearest_neighbor_);
@@ -198,12 +225,14 @@ void PictureLayer::FromLayerSpecificPropertiesProto(
   // If this is a new layer, ensure it has a recording source. During layer
   // hierarchy deserialization, ::SetLayerTreeHost(...) is not called, but
   // instead the member is set directly, so it needs to be set here explicitly.
-  if (!recording_source_)
+  if (!recording_source_) {
     recording_source_.reset(new RecordingSource);
+    // A RecordingSource is only ever deserialized on the client.
+    recording_source_->set_client_picture_cache(
+        layer_tree_host()->client_picture_cache());
+  }
 
-  recording_source_->FromProtobuf(
-      picture.recording_source(),
-      layer_tree_host()->image_serialization_processor());
+  recording_source_->FromProtobuf(picture.recording_source());
 
   Region new_invalidation = RegionFromProto(picture.invalidation());
   last_updated_invalidation_.Swap(&new_invalidation);