Introduce ViewRoot to forward input/view events to native

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/jni_weak_ref.h"
+#include "base/callback.h"
 #include "base/memory/ref_counted.h"
 #include "ui/android/ui_android_export.h"
 #include "ui/gfx/geometry/rect_f.h"
 
+typedef unsigned int SkColor;
+
 namespace cc {
 class Layer;
 }
 
 namespace ui {
 
 class WindowAndroid;
 
 // A simple container for a UI layer.
 // At the root of the hierarchy is a WindowAndroid, when attached.
@@ skipping 22 matching lines @@
    private:
     // TODO(jinsukkim): Following weak refs can be cast to strong refs which
     //     cannot be garbage-collected and leak memory. Rewrite not to use them.
     //     see comments in crrev.com/2103243002.
     JavaObjectWeakGlobalRef view_;
     JavaObjectWeakGlobalRef delegate_;
 
     // Default copy/assign disabled by move constructor.
   };
 
-  // A ViewAndroid may have its own delegate or otherwise will
-  // use the next available parent's delegate.
-  ViewAndroid(const base::android::JavaRef<jobject>& delegate);
-
   ViewAndroid();
   virtual ~ViewAndroid();
 
   // Returns the window at the root of this hierarchy, or |null|
   // if disconnected.
   virtual WindowAndroid* GetWindowAndroid() 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);
 
   void SetDelegate(const base::android::JavaRef<jobject>& delegate);
 
   // Adds this view as a child of another view.
   void AddChild(ViewAndroid* child);
 
   // Detaches this view from its parent.
   void RemoveFromParent();
 
   bool StartDragAndDrop(const base::android::JavaRef<jstring>& jtext,
                         const base::android::JavaRef<jobject>& jimage);
 
   ScopedAnchorView AcquireAnchorView();
   void SetAnchorRect(const base::android::JavaRef<jobject>& anchor,
                      const gfx::RectF& bounds);
 
+  void reset_physical_backing_size_changed_handler(
+      base::RepeatingCallback<void(int, int)> handler) {
+    // Handlers are stored in the view android that has the java delegate,
+    // which is unique in the implementation.
+    //
+    // This should be able to find the one to store the handler in before
+    // reaching the top view (or window, if not attached yet).
+    DCHECK(parent_);
+    if (delegate_.is_uninitialized())
+      parent_->reset_physical_backing_size_changed_handler(handler);
+    else
+      physical_backing_size_changed_handler_ = std::move(handler);
+  }
+
+  void reset_physical_backing_size_changed_handler() {
+    DCHECK(parent_);
+    if (delegate_.is_uninitialized())
+      parent_->reset_physical_backing_size_changed_handler();
+    else
+      physical_backing_size_changed_handler_.Reset();
+  }
+
+  void OnPhysicalBackingSizeChanged(
+      JNIEnv* env,
+      const base::android::JavaParamRef<jobject>& obj,
+      jint width,
+      jint height);
+
+  // Register the ViewAndroid's native methods through JNI.
+  static bool RegisterViewAndroid(JNIEnv* env);
+
  protected:
   ViewAndroid* parent_;
 
  private:
   void RemoveChild(ViewAndroid* child);
 
   // 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::ScopedJavaLocalRef<jobject>
       GetViewAndroidDelegate() const;
 
   std::list<ViewAndroid*> children_;
   scoped_refptr<cc::Layer> layer_;
   JavaObjectWeakGlobalRef delegate_;
 
+  // Handler for calls coming down from Java layer.
+  base::RepeatingCallback<void(int, int)>
+      physical_backing_size_changed_handler_;
+
   DISALLOW_COPY_AND_ASSIGN(ViewAndroid);
 };
 
 }  // namespace ui
 
 #endif  // UI_ANDROID_VIEW_ANDROID_H_