Fix compiler warnings.

views/controls/slider/slider.h

 // Copyright (c) 2009 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_SLIDER_SLIDER_H_
 #define VIEWS_CONTROLS_SLIDER_SLIDER_H_
 
 #if defined(OS_LINUX)
 #include <gdk/gdk.h>
 #endif
@@ skipping 33 matching lines @@
 
   Slider();
   Slider(double min, double max, double step, StyleFlags style,
          SliderListener* listener);
   virtual ~Slider();
 
   // Cause the slider to notify the listener that the value has changed.
   virtual void NotifyValueChanged();
 
   // Gets/Sets the value in the slider.
-  const double value() const { return value_; }
+  double value() const { return value_; }
   void SetValue(double value);
 
   // Accessor for |style_|.
   StyleFlags style() const { return style_; }
 
   // Accessor for |min_|.
-  const double min() const { return min_; }
+  double min() const { return min_; }
 
   // Accessor for |max_|.
-  const double max() const { return max_; }
+  double max() const { return max_; }
 
   // Accessor for |step_|.
-  const double step() const { return step_; }
+  double step() const { return step_; }
 
   // Overridden from View:
   virtual void Layout();
   virtual gfx::Size GetPreferredSize();
   virtual bool IsFocusable() const;
   virtual void SetEnabled(bool enabled);
   virtual void PaintFocusBorder(gfx::Canvas* canvas);
 
  protected:
   virtual void Focus();
@@ skipping 25 matching lines @@
 
   // The value displayed in the slider.
   double value_;
 
   DISALLOW_COPY_AND_ASSIGN(Slider);
 };
 
 }  // namespace views
 
 #endif  // VIEWS_CONTROLS_SLIDER_SLIDER_H_