Factor out ContentViewAndroidDelegate

ui/android/view_android.h

 // 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.
 
 #ifndef UI_ANDROID_VIEW_ANDROID_H_
 #define UI_ANDROID_VIEW_ANDROID_H_
 
 #include <list>
 
 #include "base/android/scoped_java_ref.h"
 #include "base/memory/ref_counted.h"
 #include "ui/android/ui_android_export.h"
+#include "ui/gfx/geometry/rect_f.h"
 
 namespace cc {
 class Layer;
 }
 
 namespace ui {
 
 class WindowAndroid;
 
 // A simple container for a UI layer.
 // At the root of the hierarchy is a WindowAndroid.
 //
 class UI_ANDROID_EXPORT ViewAndroid {
  public:
   // Used to construct a root view.
   ViewAndroid(const base::android::JavaRef<jobject>& delegate,
               WindowAndroid* root_window);
 
+  static bool RegisterWindowAndroid(JNIEnv* env);
+
   // Used to construct a child view.
   ViewAndroid();
   ~ViewAndroid();
 
   // Returns the window at the root of this hierarchy, or |null|
   // if disconnected.
   WindowAndroid* GetWindowAndroid() const;
 
   // Set the root |WindowAndroid|. This is only valid for root
   // nodes and must not be called for children.
   void SetWindowAndroid(WindowAndroid* root_window);
 
-  // Returns the Java delegate for this view. This is used to delegate work
-  // up to the embedding view (or the embedder that can deal with the
-  // implementation details).
-  const base::android::JavaRef<jobject>& GetViewAndroidDelegate() const;
-
   // Used to return and set the layer for this view. May be |null|.
   cc::Layer* GetLayer() const;
   void SetLayer(scoped_refptr<cc::Layer> layer);
 
   // Add/remove this view as a child of another view.
   void AddChild(ViewAndroid* child);
   void RemoveChild(ViewAndroid* child);
 
+  // Stores an anchored view to delete itself at the end of its lifetime
+  // automatically. This helps manage the lifecyle without the dependency
+  // on |ViewAndroid|.
+  class ScopedAnchorView {
+   public:
+    ScopedAnchorView(const base::android::JavaRef<jobject>& jview,
+                     const base::android::JavaRef<jobject>& jdelegate)
+        : view_(jview), delegate_(jdelegate) { }
+
+    ScopedAnchorView() : ScopedAnchorView(nullptr, nullptr) { }
+
+    // Calls JNI removeView() on the delegate for cleanup.
+    ~ScopedAnchorView();
+
+    base::android::ScopedJavaGlobalRef<jobject> ref() const { return view_; }
+    jobject obj() const { return view_.obj(); }

[no sievers, 2016/07/18 22:14:17]

nit: Could this just have one method to return 'const JavaRef<jobject>&' instead
of ref() and obj()?

JavaRef<> has obj() as a method anyways.

[Jinsuk Kim, 2016/07/19 07:08:40]

Done. Also added |is_null()| to not to have to call |view().is_null()|.

+
+   private:
+    base::android::ScopedJavaGlobalRef<jobject> view_;
+    base::android::ScopedJavaGlobalRef<jobject> delegate_;
+  };
+
+  ScopedAnchorView* AcquireAnchorView();

[no sievers, 2016/07/18 22:14:17]

Can you make this a 'move only' type and return by value instead of as a heap
object?

You only need to define a move constructor that takes an rvalue reference (maybe
'=' operator also for completeness).
That will automatically delete the default copy constructor also, making it
'move only'.

ScopedAnchorView(ScopedAnchorView&& other) {
  JNIEnv* env = base::android::AttachCurrentThread();
  view_.Reset(env, other.view_.Release());
  delegate_.Reset(env, other.delegate_.Release());
}

[Jinsuk Kim, 2016/07/19 07:08:40]

Done. The way I changed it uses move assignment though. Please see if it looks
like what you had in mind.

+  void SetAnchorRect(const base::android::JavaRef<jobject>& anchor,
+                     const gfx::RectF& bounds);
+
  private:
+  // Returns the Java delegate for this view. This is used to delegate work
+  // up to the embedding view (or the embedder that can deal with the
+  // implementation details).
+  const base::android::JavaRef<jobject>& GetViewAndroidDelegate() const;
+
   ViewAndroid* parent_;
   std::list<ViewAndroid*> children_;
   WindowAndroid* window_;
   scoped_refptr<cc::Layer> layer_;
   base::android::ScopedJavaGlobalRef<jobject> delegate_;
 
   DISALLOW_COPY_AND_ASSIGN(ViewAndroid);
 };
 
 }  // namespace ui
 
 #endif  // UI_ANDROID_VIEW_ANDROID_H_