views: Factor out SingleSplitView Observer into SingleSplitViewListener.

views/controls/single_split_view.h

 // Copyright (c) 2011 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 VIEWS_CONTROLS_SINGLE_SPLIT_VIEW_H_
 #define VIEWS_CONTROLS_SINGLE_SPLIT_VIEW_H_
 #pragma once
 
 #include "base/gtest_prod_util.h"
 #include "views/view.h"
 
 namespace views {
 
+class SingleSplitViewListener;
+
 // SingleSplitView lays out two views next to each other, either horizontally
 // or vertically. A splitter exists between the two views that the user can
 // drag around to resize the views.
-// Observer's SplitHandleMoved notification helps to monitor user initiated
-// layout changes.
+// SingleSplitViewListener's SplitHandleMoved notification helps to monitor user
+// initiated layout changes.
 class VIEWS_EXPORT SingleSplitView : public View {
  public:
   enum Orientation {
     HORIZONTAL_SPLIT,
     VERTICAL_SPLIT
   };
 
-  // Internal class name
   static const char kViewClassName[];
 
-  class Observer {
-   public:
-    // Invoked when split handle is moved by the user. |source|'s divider_offset
-    // is already set to the new value, but Layout has not happened yet.
-    // Returns false if the layout has been handled by the observer, returns
-    // true if |source| should do it by itself.
-    virtual bool SplitHandleMoved(SingleSplitView* source) = 0;
-   protected:
-    virtual ~Observer() {}
-  };
-
   SingleSplitView(View* leading,
                   View* trailing,
                   Orientation orientation,
-                  Observer* observer);
+                  SingleSplitViewListener* listener);
 
   virtual void Layout() OVERRIDE;
   virtual std::string GetClassName() const OVERRIDE;
 
   virtual void GetAccessibleState(ui::AccessibleViewState* state) OVERRIDE;
 
   // SingleSplitView's preferred size is the sum of the preferred widths
   // and the max of the heights.
   virtual gfx::Size GetPreferredSize() OVERRIDE;
 
@@ skipping 34 matching lines @@
 
  private:
   // This test calls OnMouse* functions.
   FRIEND_TEST_ALL_PREFIXES(SingleSplitViewTest, MouseDrag);
 
   // Returns true if |x| or |y| is over the divider.
   bool IsPointInDivider(const gfx::Point& p);
 
   // Calculates the new |divider_offset| based on the changes of split view
   // bounds.
-  int CalculateDividerOffset(
-      int divider_offset,
-      const gfx::Rect& previous_bounds,
-      const gfx::Rect& new_bounds) const;
+  int CalculateDividerOffset(int divider_offset,
+                             const gfx::Rect& previous_bounds,
+                             const gfx::Rect& new_bounds) const;
 
   // Returns divider offset within primary axis size range for given split
   // view |bounds|.
   int NormalizeDividerOffset(int divider_offset, const gfx::Rect& bounds) const;
 
   // Returns width in case of horizontal split and height otherwise.
   int GetPrimaryAxisSize() const {
     return GetPrimaryAxisSize(width(), height());
   }
 
@@ skipping 12 matching lines @@
   DragInfo drag_info_;
 
   // Orientation of the split view.
   bool is_horizontal_;
 
   // Position of the divider.
   int divider_offset_;
 
   bool resize_leading_on_bounds_change_;
 
-  // Observer to notify about user initiated handle movements. Not own by us.
-  Observer* observer_;
+  // Listener to notify about user initiated handle movements. Not owned.
+  SingleSplitViewListener* listener_;
 
   // The accessible name of this view.
   string16 accessible_name_;
 
   DISALLOW_COPY_AND_ASSIGN(SingleSplitView);
 };
 
 }  // namespace views
 
 #endif  // VIEWS_CONTROLS_SINGLE_SPLIT_VIEW_H_