[Android] Implementation of overscroll effect for Android L

content/browser/android/edge_effect_base.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_BASE_H_
+#define CONTENT_BROWSER_ANDROID_EDGE_EFFECT_BASE_H_
+
+#include "base/basictypes.h"
+#include "base/time/time.h"
+#include "ui/gfx/geometry/size_f.h"
+#include "ui/gfx/transform.h"
+
+namespace cc {
+class Layer;
+}
+
+namespace content {
+
+// A base class for overscroll-related Android effects.
+class EdgeEffectBase {
+ public:
+  enum State {
+    STATE_IDLE = 0,
+    STATE_PULL,
+    STATE_ABSORB,
+    STATE_RECEDE,
+    STATE_PULL_DECAY
+  };
+
+  virtual ~EdgeEffectBase() {}
+
+  virtual void Pull(base::TimeTicks current_time, float delta_distance) = 0;

[aelias_OOO_until_Jul13, 2014/08/14 22:54:19]

This variant seems unnecessary, can we remove it?  Note that overloading is
moderately discouraged by the style guide.

[jdduke (slow), 2014/08/15 19:15:06]

Yeah, looks like they kept it in the Android framework for compatibility
reasons, but we don't need the old signature.

+  virtual void Pull(base::TimeTicks current_time,
+                    float delta_distance,
+                    float displacement) = 0;
+  virtual void Absorb(base::TimeTicks current_time, float velocity) = 0;
+  virtual bool Update(base::TimeTicks current_time) = 0;
+  virtual void Release(base::TimeTicks current_time) = 0;
+
+  virtual void Finish() = 0;
+  virtual bool IsFinished() const = 0;
+
+  virtual void ApplyToLayers(const gfx::SizeF& size,
+                             const gfx::Transform& transform) = 0;
+  virtual void SetParent(cc::Layer* parent) = 0;
+};
+
+}  // namespace content
+
+#endif  // CONTENT_BROWSER_ANDROID_EDGE_EFFECT_BASE_H_