android: Migrate old content readback to use async readback (and delegated renderer)

content/browser/android/transient_ui_resource.cc

+// 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 "content/browser/android/transient_ui_resource.h"
+
+#include "base/basictypes.h"
+#include "base/bind.h"
+#include "cc/resources/ui_resource_bitmap.h"
+#include "cc/trees/layer_tree_host.h"
+#include "third_party/skia/include/core/SkBitmap.h"
+
+namespace content {
+
+scoped_ptr<TransientUIResource> TransientUIResource::Create(
+    cc::LayerTreeHost* host,
+    const cc::UIResourceBitmap& bitmap) {
+  return make_scoped_ptr(new TransientUIResource(host, bitmap));
+}
+
+TransientUIResource::TransientUIResource(cc::LayerTreeHost* host,
+                                         const cc::UIResourceBitmap& bitmap)
+  : bitmap_(new cc::UIResourceBitmap(bitmap)), host_(host) {
+  DCHECK(host_);
+  id_ = host_->CreateUIResource(this);
+}
+
+// User must make sure that host is still valid before this object goes out of
+// scope.
+TransientUIResource::~TransientUIResource() {
+  if (id_) {
+    DCHECK(host_);
+    host_->DeleteUIResource(id_);
+  }
+}
+
+cc::UIResourceBitmap TransientUIResource::GetBitmap(cc::UIResourceId uid,
+                                                    bool resource_lost) {
+  if (bitmap_) {
+    cc::UIResourceBitmap out_bitmap = *bitmap_.get();
+    // Frees the bitmap after it's been accessed.
+    bitmap_.reset();
+    return out_bitmap;
+  }
+
+  SkBitmap place_holder;
+  place_holder.setConfig(SkBitmap::kARGB_8888_Config, 1, 1);
+  place_holder.allocPixels();
+  place_holder.setImmutable();
+  return cc::UIResourceBitmap(place_holder);
+}
+
+}  // namespace content