aura: Allow delegated frames to be used by more than one impl layer.

cc/layers/delegated_frame_resource_collection.cc

Index: cc/layers/delegated_frame_resource_collection.cc
diff --git a/cc/layers/delegated_frame_resource_collection.cc b/cc/layers/delegated_frame_resource_collection.cc
new file mode 100644
index 0000000000000000000000000000000000000000..565824f01320b0b7cb24f29015e783e4f0dca6e8
--- /dev/null
+++ b/cc/layers/delegated_frame_resource_collection.cc
@@ -0,0 +1,97 @@
+// Copyright 2013 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#include "cc/layers/delegated_frame_resource_collection.h"
+
+#include "base/bind.h"
+#include "cc/trees/blocking_task_runner.h"
+
+namespace cc {
+
+DelegatedFrameResourceCollection::DelegatedFrameResourceCollection(
+    DelegatedFrameResourceCollectionClient* client)
+    : client_(client),
+      main_thread_runner_(BlockingTaskRunner::current()),
+      weak_ptrs_(this) {
+  DCHECK(main_thread_checker_.CalledOnValidThread());
+}
+
+DelegatedFrameResourceCollection::~DelegatedFrameResourceCollection() {
+  DCHECK_EQ(0u, returned_resources_for_child_compositor_.size());
+  DCHECK(main_thread_checker_.CalledOnValidThread());
+}
+
+void DelegatedFrameResourceCollection::TakeUnusedResourcesForChildCompositor(
+    ReturnedResourceArray* array) {
+  DCHECK(main_thread_checker_.CalledOnValidThread());
+  DCHECK(array->empty());
+  array->swap(returned_resources_for_child_compositor_);
+}
+
+void DelegatedFrameResourceCollection::ReceivedResources(
+    const TransferableResourceArray& resources) {
+  DCHECK(main_thread_checker_.CalledOnValidThread());
+  for (size_t i = 0; i < resources.size(); ++i)
+    resource_id_ref_count_map_[resources[i].id].refs_to_return++;
+}
+
+void DelegatedFrameResourceCollection::ReturnResources(
+    const ReturnedResourceArray& returned) {
+  DCHECK(main_thread_checker_.CalledOnValidThread());
+  returned_resources_for_child_compositor_.insert(
+      returned_resources_for_child_compositor_.end(),
+      returned.begin(),
+      returned.end());
+  if (client_ && !returned.empty())
+    client_->UnusedResourcesAreAvailable();
+}
+
+void DelegatedFrameResourceCollection::RefResources(
+    const TransferableResourceArray& resources) {
+  DCHECK(main_thread_checker_.CalledOnValidThread());
+  for (size_t i = 0; i < resources.size(); ++i)
+    resource_id_ref_count_map_[resources[i].id].refs_to_wait_for++;
+}
+
+ReturnCallback
+DelegatedFrameResourceCollection::GetReturnResourcesCallbackForImplThread() {
+  return base::Bind(
+      &DelegatedFrameResourceCollection::UnrefResourcesOnImplThread,
+      main_thread_runner_,
+      weak_ptrs_.GetWeakPtr());
+}
+
+void DelegatedFrameResourceCollection::UnrefResources(
+    const ReturnedResourceArray& returned) {
+  DCHECK(main_thread_checker_.CalledOnValidThread());
+
+  ReturnedResourceArray to_return;
+
+  for (size_t i = 0; i < returned.size(); ++i) {
+    ResourceIdRefCountMap::iterator it =
+        resource_id_ref_count_map_.find(returned[i].id);
+    DCHECK(it != resource_id_ref_count_map_.end());
+    DCHECK_GE(it->second.refs_to_wait_for, returned[i].count);
+    it->second.refs_to_wait_for -= returned[i].count;
+    if (it->second.refs_to_wait_for == 0) {
+      to_return.push_back(returned[i]);
+      to_return.back().count = it->second.refs_to_return;
+      resource_id_ref_count_map_.erase(it);
+    }
+  }
+  ReturnResources(to_return);
+}
+
+// static
+void DelegatedFrameResourceCollection::UnrefResourcesOnImplThread(
+    scoped_refptr<BlockingTaskRunner> main_thread_runner,
+    base::WeakPtr<DelegatedFrameResourceCollection> self,
+    const ReturnedResourceArray& returned) {
+  main_thread_runner->PostTask(
+      FROM_HERE,
+      base::Bind(
+          &DelegatedFrameResourceCollection::UnrefResources, self, returned));
+}
+
+}  // namespace cc