[Android] Add slack to allow refresh after overscrolling

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/android/resources/resource_manager.h"
 #include "ui/android/resources/system_ui_resource_type.h"
@@ skipping 193 matching lines @@
 
   bool one_last_frame = false;
   if (state_ == STATE_RECEDE && glow_scale_y_ <= 0) {
     Finish();
     one_last_frame = true;
   }
 
   return !IsFinished() || one_last_frame;
 }
 
+float EdgeEffectL::GetAlpha() const {
+  return IsFinished() ? 0.f : glow_alpha_;
+}
+
 void EdgeEffectL::ApplyToLayers(const gfx::SizeF& size,
                                 const gfx::Transform& transform) {
   if (IsFinished())
     return;
 
   // An empty window size, while meaningless, is also relatively harmless, and
   // will simply prevent any drawing of the layers.
   if (size.IsEmpty()) {
     glow_->SetIsDrawable(false);
     return;
@@ skipping 33 matching lines @@
 }
 
 // static
 void EdgeEffectL::PreloadResources(ui::ResourceManager* resource_manager) {
   DCHECK(resource_manager);
   resource_manager->PreloadResource(ui::ANDROID_RESOURCE_TYPE_SYSTEM,
                                     kResourceId);
 }
 
 }  // namespace content