[Android] Add slack to allow refresh after overscrolling

content/browser/android/edge_effect.h

 // Copyright (c) 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 CONTENT_BROWSER_ANDROID_EDGE_EFFECT_H_
 #define CONTENT_BROWSER_ANDROID_EDGE_EFFECT_H_
 
 #include "base/memory/scoped_ptr.h"
 #include "content/browser/android/edge_effect_base.h"
 
@@ skipping 19 matching lines @@
 
   void Pull(base::TimeTicks current_time,
             float delta_distance,
             float displacement) override;
   void Absorb(base::TimeTicks current_time, float velocity) override;
   bool Update(base::TimeTicks current_time) override;
   void Release(base::TimeTicks current_time) override;
 
   void Finish() override;
   bool IsFinished() const override;
+  float GetAlpha() const override;
 
   void ApplyToLayers(const gfx::SizeF& size,
                      const gfx::Transform& transform) override;
   void SetParent(cc::Layer* parent) override;
 
   // Thread-safe trigger to load resources.
   static void PreloadResources(ui::ResourceManager* resource_manager);
 
  private:
   class EffectLayer;
@@ skipping 23 matching lines @@
   State state_;
 
   float pull_distance_;
 
   DISALLOW_COPY_AND_ASSIGN(EdgeEffect);
 };
 
 }  // namespace content
 
 #endif  // CONTENT_BROWSER_ANDROID_EDGE_EFFECT_H_