[Android] Add a native pull-to-refresh overscroll effect

content/browser/android/edge_effect_l.cc

 // Copyright 2014 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.
 
 #include "content/browser/android/edge_effect_l.h"
 
 #include "cc/layers/ui_resource_layer.h"
+#include "content/browser/android/animation_utils.h"
 #include "ui/base/android/system_ui_resource_manager.h"
 
 namespace content {
 
 namespace {
 
 // Time it will take the effect to fully recede in ms
 const int kRecedeTimeMs = 600;
 
 // Time it will take before a pulled glow begins receding in ms
@@ skipping 15 matching lines @@
 
 const float kSin = 0.5f;    // sin(PI / 6)
 const float kCos = 0.866f;  // cos(PI / 6);
 
 // How much dragging should effect the height of the glow image.
 // Number determined by user testing.
 const float kPullDistanceAlphaGlowFactor = 0.8f;
 
 const int kVelocityGlowFactor = 6;
 
-const ui::SystemUIResourceManager::ResourceType kResourceType =
-    ui::SystemUIResourceManager::OVERSCROLL_GLOW_L;
-
-template <typename T>
-T Lerp(T a, T b, T t) {
-  return a + (b - a) * t;
-}
-
-template <typename T>
-T Clamp(T value, T low, T high) {
-  return value < low ? low : (value > high ? high : value);
-}
-
-template <typename T>
-T Damp(T input, T factor) {
-  T result;
-  if (factor == 1) {
-    result = 1 - (1 - input) * (1 - input);
-  } else {
-    result = 1 - std::pow(1 - input, 2 * factor);
-  }
-  return result;
-}
+const ui::SystemUIResourceType kResourceType = ui::OVERSCROLL_GLOW_L;
 
 }  // namespace
 
 EdgeEffectL::EdgeEffectL(ui::SystemUIResourceManager* resource_manager)
     : resource_manager_(resource_manager),
       glow_(cc::UIResourceLayer::Create()),
       glow_alpha_(0),
       glow_scale_y_(0),
       glow_alpha_start_(0),
       glow_alpha_finish_(0),
@@ skipping 201 matching lines @@
 }
 
 // static
 void EdgeEffectL::PreloadResources(
     ui::SystemUIResourceManager* resource_manager) {
   DCHECK(resource_manager);
   resource_manager->PreloadResource(kResourceType);
 }
 
 }  // namespace content