cc: Split ReleaseResources into Release and Recreate.

cc/trees/layer_tree_host_impl.cc

Index: cc/trees/layer_tree_host_impl.cc
diff --git a/cc/trees/layer_tree_host_impl.cc b/cc/trees/layer_tree_host_impl.cc
index f51c61ac2fd55faa576b0ea64255d26d90705fd5..f376998427462de90d39825bb1aaa0dd58270088 100644
--- a/cc/trees/layer_tree_host_impl.cc
+++ b/cc/trees/layer_tree_host_impl.cc
@@ -116,6 +116,21 @@ class ViewportAnchor {
   gfx::ScrollOffset viewport_in_content_coordinates_;
 };
 
+template <typename Object>
+class ScopedCaller {

[danakj, 2015/02/05 20:45:49]

did you look around in base/ for something like this btw? maybe there is
something.. tho it'd probably use Callback.

[vmpstr, 2015/02/05 21:41:32]

I couldn't really find anything that would do a similar thing. The closest is
ScopedClosureRunner, but it just runs a given closure in the dtor.

+ public:
+  using Function = void (Object::*)();
+  ScopedCaller(Object* object, Function on_entry, Function on_exit)
+      : object_(object), on_exit_(on_exit) {
+    (object_->*on_entry)();
+  }
+
+  ~ScopedCaller() { (object_->*on_exit_)(); }
+
+ private:
+  Object* object_;
+  Function on_exit_;
+};
 
 void DidVisibilityChange(LayerTreeHostImpl* id, bool visible) {
   if (visible) {
@@ -1611,7 +1626,9 @@ void LayerTreeHostImpl::SetUseGpuRasterization(bool use_gpu) {
 
   // Clean up and replace existing tile manager with another one that uses
   // appropriate rasterizer.
-  ReleaseTreeResources();
+  ScopedCaller<LayerTreeHostImpl> scoped_release_resources(
+      this, &LayerTreeHostImpl::ReleaseTreeResources,
+      &LayerTreeHostImpl::RecreateTreeResources);
   if (tile_manager_) {
     DestroyTileManager();
     CreateAndSetTileManager();
@@ -1934,6 +1951,14 @@ void LayerTreeHostImpl::ReleaseTreeResources() {
   EvictAllUIResources();
 }
 
+void LayerTreeHostImpl::RecreateTreeResources() {
+  active_tree_->RecreateResources();
+  if (pending_tree_)
+    pending_tree_->RecreateResources();
+  if (recycle_tree_)
+    recycle_tree_->RecreateResources();
+}
+
 void LayerTreeHostImpl::CreateAndSetRenderer() {
   DCHECK(!renderer_);
   DCHECK(output_surface_);
@@ -2125,8 +2150,12 @@ bool LayerTreeHostImpl::InitializeRenderer(
   resource_provider_ = nullptr;
   output_surface_ = nullptr;
 
-  if (!output_surface->BindToClient(this))
+  if (!output_surface->BindToClient(this)) {
+    // Avoid recreating tree resources because we might not have enough
+    // information to do this yet (eg. we don't have a TileManager at this
+    // point).
     return false;
+  }
 
   output_surface_ = output_surface.Pass();
   resource_provider_ = ResourceProvider::Create(
@@ -2143,6 +2172,7 @@ bool LayerTreeHostImpl::InitializeRenderer(
 
   if (settings_.impl_side_painting)
     CreateAndSetTileManager();
+  RecreateTreeResources();
 
   // Initialize vsync parameters to sane values.
   const base::TimeDelta display_refresh_interval =
@@ -2183,7 +2213,9 @@ void LayerTreeHostImpl::DeferredInitialize() {
   DCHECK(settings_.impl_side_painting);
   DCHECK(output_surface_->context_provider());
 
-  ReleaseTreeResources();
+  ScopedCaller<LayerTreeHostImpl> scoped_release_resources(

[enne (OOO), 2015/02/05 20:43:52]

This seems like overkill.  Neither of the functions this is in has an early out,
so maybe just call the two functions you need?

Also, this is only valid for picture layers, so maybe DestroyTileManager and
CreateAndSetTileManager could just make these recreate/release calls?

[vmpstr, 2015/02/05 21:41:32]

It's ReleaseResources is also implemented in textured layer and video layer, so
I'd prefer to keep the two calls outside of tile manager specific stuff. I
changed this to be explicit calls.

+      this, &LayerTreeHostImpl::ReleaseTreeResources,
+      &LayerTreeHostImpl::RecreateTreeResources);
   renderer_ = nullptr;
   DestroyTileManager();
 
@@ -2201,7 +2233,9 @@ void LayerTreeHostImpl::ReleaseGL() {
   DCHECK(settings_.impl_side_painting);
   DCHECK(output_surface_->context_provider());
 
-  ReleaseTreeResources();
+  ScopedCaller<LayerTreeHostImpl> scoped_release_resources(
+      this, &LayerTreeHostImpl::ReleaseTreeResources,
+      &LayerTreeHostImpl::RecreateTreeResources);
   renderer_ = nullptr;
   DestroyTileManager();