Add ViewObserver to View for view updates

ui/views/devtools_observer.h

Index: ui/views/devtools_observer.h
diff --git a/ui/views/devtools_observer.h b/ui/views/devtools_observer.h
new file mode 100644
index 0000000000000000000000000000000000000000..20242b887c8e094b3452478521fbed59fa4575cc
--- /dev/null
+++ b/ui/views/devtools_observer.h
@@ -0,0 +1,43 @@
+// Copyright (c) 2016 The Chromium Authors. All rights reserved.

[sadrul, 2016/11/18 19:07:51]

No (c)

[Sarmad Hashmi, 2016/11/19 00:29:51]

Done.

+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#ifndef UI_VIEWS_DEVTOOLS_OBSERVER_H_
+#define UI_VIEWS_DEVTOOLS_OBSERVER_H_
+
+#include "ui/views/view.h"
+#include "ui/views/views_export.h"
+
+namespace gfx {
+class Rect;
+}
+
+namespace views {
+
+// DevTools specific observer for View changes.
+class VIEWS_EXPORT DevToolsObserver {
+ public:
+  // Called whenever target |view| is being moved. If |old_parent| is NULL,
+  // the target is being added. If the |new_parent| is NULL, then the target
+  // is being removed.
+  virtual void OnViewHierarchyChanged(View* target,
+                                      View* old_parent,
+                                      View* new_parent) {}
+
+  virtual void OnViewVisibilityChanged(View* view, bool visible) {}
+
+  virtual void OnViewEnabledChanged(View* view, int index) {}
+
+  virtual void OnViewBoundsChanged(View* view, const gfx::Rect& new_bounds) {}
+
+  // Invoked whenever a child is moved to another index. This is called on the
+  // parent view. |view| is the child view being reordered to the index.
+  virtual void OnChildViewReordered(View* view, int index) {}
+
+ protected:
+  virtual ~DevToolsObserver() {}
+};
+
+}  // namespace views
+
+#endif  // UI_VIEWS_DEVTOOLS_OBSERVER_H_