Add ViewObserver to View for view updates

ui/views/view.h

Index: ui/views/view.h
diff --git a/ui/views/view.h b/ui/views/view.h
index 050548f0120ac7c90a3e5630966e5177208db8cf..72b5390c89a40731c876cf6a028e93add7bcbbed 100644
--- a/ui/views/view.h
+++ b/ui/views/view.h
@@ -70,6 +70,7 @@ namespace views {
 class Background;
 class Border;
 class ContextMenuController;
+class DevToolsObserver;
 class DragController;
 class FocusManager;
 class FocusTraversable;
@@ -1002,6 +1003,12 @@ class VIEWS_EXPORT View : public ui::LayerDelegate,
   virtual int GetLineScrollIncrement(ScrollView* scroll_view,
                                      bool is_horizontal, bool is_positive);
 
+  // DevTools Observer ---------------------------------------------------------
+
+  void set_devtools_observer(DevToolsObserver* devtools_observer) {
+    devtools_observer_ = devtools_observer;
+  };
+
  protected:
   // Used to track a drag. RootView passes this into
   // ProcessMousePressed/Dragged.
@@ -1577,6 +1584,10 @@ class VIEWS_EXPORT View : public ui::LayerDelegate,
   // so we can't use a scoped_ptr. It's dereferenced in the destructor.
   NativeViewAccessibility* native_view_accessibility_;
 
+  // Observers -------------------------------------------------------------
+
+  DevToolsObserver* devtools_observer_;
+
   DISALLOW_COPY_AND_ASSIGN(View);
 };