[Android] Upstream scene layers

chrome/browser/android/compositor/scene_layer/scene_layer.h

+// Copyright 2015 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.
+
+#ifndef CHROME_BROWSER_ANDROID_COMPOSITOR_SCENE_LAYER_SCENE_LAYER_H_
+#define CHROME_BROWSER_ANDROID_COMPOSITOR_SCENE_LAYER_SCENE_LAYER_H_
+
+#include <jni.h>
+
+#include "base/android/jni_weak_ref.h"
+#include "base/android/scoped_java_ref.h"
+#include "base/basictypes.h"
+#include "base/memory/ref_counted.h"
+#include "third_party/skia/include/core/SkColor.h"
+
+namespace cc {
+class Layer;
+}
+
+namespace chrome {
+namespace android {
+
+// A native-side, cc::Layer based representation of how a scene should be drawn.
+// Basically, this is a wrapper around cc::Layer and bridge with its Java
+// counterpart.
+class SceneLayer {
+ public:
+  static SceneLayer* FromJavaObject(JNIEnv* env, jobject jobj);
+
+  // Create SceneLayer and creates an empty cc::Layer.
+  SceneLayer(JNIEnv* env, jobject jobj);
+  // Create SceneLayer with the already-instantiated |layer|.
+
+  SceneLayer(JNIEnv* env, jobject jobj, scoped_refptr<cc::Layer> layer);
+  virtual ~SceneLayer();
+
+  // Notifies that this scene layer is about to be detached from its parent.
+  // TODO(changwan): check if we can remove this.
+  virtual void OnDetach();
+
+  // Java SceneLayer can use this method to destroy its native-side counterpart.
+  virtual void Destroy(JNIEnv* env, jobject jobj);
+
+  // Returns cc::Layer object that this SceneLayer contains.
+  scoped_refptr<cc::Layer> layer() { return layer_; }
+
+  // Returns whether we should show background when we draw this SceneLayer.
+  virtual bool ShouldShowBackground();
+
+  // Returns the background color if it is needed.
+  virtual SkColor GetBackgroundColor();
+
+ protected:
+  JavaObjectWeakGlobalRef weak_java_scene_layer_;
+  scoped_refptr<cc::Layer> layer_;
+
+ private:
+  DISALLOW_COPY_AND_ASSIGN(SceneLayer);
+};
+
+bool RegisterSceneLayer(JNIEnv* env);
+
+}  // namespace android
+}  // namespace chrome
+
+#endif  // CHROME_BROWSER_ANDROID_COMPOSITOR_SCENE_LAYER_SCENE_LAYER_H_