[Android] Use UIResource for overscroll glow

content/browser/android/edge_effect.cc

Index: content/browser/android/edge_effect.cc
diff --git a/content/browser/android/edge_effect.cc b/content/browser/android/edge_effect.cc
index 94e5b512e20505bf5ad12c59f9258e88f9fa41b1..2979872723eaf3eae969792667b6fbcce687f1cd 100644
--- a/content/browser/android/edge_effect.cc
+++ b/content/browser/android/edge_effect.cc
@@ -5,6 +5,8 @@
 #include "content/browser/android/edge_effect.h"
 
 #include "cc/layers/layer.h"
+#include "cc/layers/ui_resource_layer.h"
+#include "ui/base/android/system_ui_resource_manager.h"
 
 namespace content {
 
@@ -118,52 +120,70 @@ gfx::Size ComputeBounds(EdgeEffect::Edge edge,
   };
 }
 
-void DisableLayer(cc::Layer* layer) {
-  DCHECK(layer);
-  layer->SetIsDrawable(false);
-  layer->SetTransform(gfx::Transform());
-  layer->SetOpacity(1.f);
-}
+}  // namespace
 
-void UpdateLayer(cc::Layer* layer,
-                 EdgeEffect::Edge edge,
-                 const gfx::SizeF& window_size,
-                 int offset,
-                 int height,
-                 float opacity) {
-  DCHECK(layer);
-  layer->SetIsDrawable(true);
-  gfx::Size bounds = ComputeBounds(edge, window_size, height);
-  layer->SetTransformOrigin(
-      gfx::Point3F(bounds.width() * 0.5f, bounds.height() * 0.5f, 0));
-  layer->SetTransform(ComputeTransform(edge, window_size, offset, height));
-  layer->SetBounds(bounds);
-  layer->SetOpacity(Clamp(opacity, 0.f, 1.f));
-}
+class EdgeEffect::EffectLayer {
+ public:
+  EffectLayer(ui::SystemUIResourceManager::ResourceType resource_type,
+              ui::SystemUIResourceManager* resource_manager)
+      : ui_resource_layer_(cc::UIResourceLayer::Create()),
+        resource_type_(resource_type),
+        resource_manager_(resource_manager) {}
+
+  ~EffectLayer() { ui_resource_layer_->RemoveFromParent(); }
+
+  void SetParent(cc::Layer* parent) {
+    if (ui_resource_layer_->parent() != parent)
+      parent->AddChild(ui_resource_layer_);
+    ui_resource_layer_->SetUIResourceId(
+        resource_manager_->GetUIResourceId(resource_type_));
+  }
+
+  void Disable() { ui_resource_layer_->SetIsDrawable(false); }
+
+  void Update(EdgeEffect::Edge edge,
+              const gfx::SizeF& window_size,
+              int offset,
+              int height,
+              float opacity) {
+    ui_resource_layer_->SetUIResourceId(
+        resource_manager_->GetUIResourceId(resource_type_));
+    ui_resource_layer_->SetIsDrawable(true);
+    gfx::Size bounds = ComputeBounds(edge, window_size, height);
+    ui_resource_layer_->SetTransformOrigin(
+        gfx::Point3F(bounds.width() * 0.5f, bounds.height() * 0.5f, 0));
+    ui_resource_layer_->SetTransform(
+        ComputeTransform(edge, window_size, offset, height));
+    ui_resource_layer_->SetBounds(bounds);
+    ui_resource_layer_->SetOpacity(Clamp(opacity, 0.f, 1.f));
+  }
 
-} // namespace
-
-EdgeEffect::EdgeEffect(scoped_refptr<cc::Layer> edge,
-                       scoped_refptr<cc::Layer> glow)
-  : edge_(edge)
-  , glow_(glow)
-  , edge_alpha_(0)
-  , edge_scale_y_(0)
-  , glow_alpha_(0)
-  , glow_scale_y_(0)
-  , edge_alpha_start_(0)
-  , edge_alpha_finish_(0)
-  , edge_scale_y_start_(0)
-  , edge_scale_y_finish_(0)
-  , glow_alpha_start_(0)
-  , glow_alpha_finish_(0)
-  , glow_scale_y_start_(0)
-  , glow_scale_y_finish_(0)
-  , state_(STATE_IDLE)
-  , pull_distance_(0) {
-  // Prevent the provided layers from drawing until the effect is activated.
-  DisableLayer(edge_.get());
-  DisableLayer(glow_.get());
+  scoped_refptr<cc::UIResourceLayer> ui_resource_layer_;
+  ui::SystemUIResourceManager::ResourceType resource_type_;
+  ui::SystemUIResourceManager* resource_manager_;
+
+  DISALLOW_COPY_AND_ASSIGN(EffectLayer);
+};
+
+EdgeEffect::EdgeEffect(ui::SystemUIResourceManager* resource_manager)
+    : edge_(new EffectLayer(ui::SystemUIResourceManager::OVERSCROLL_EDGE,
+                            resource_manager)),
+      glow_(new EffectLayer(ui::SystemUIResourceManager::OVERSCROLL_GLOW,
+                            resource_manager)),
+      edge_alpha_(0),
+      edge_scale_y_(0),
+      glow_alpha_(0),
+      glow_scale_y_(0),
+      edge_alpha_start_(0),
+      edge_alpha_finish_(0),
+      edge_scale_y_start_(0),
+      edge_scale_y_finish_(0),
+      glow_alpha_start_(0),
+      glow_alpha_finish_(0),
+      glow_scale_y_start_(0),
+      glow_scale_y_finish_(0),
+      state_(STATE_IDLE),
+      pull_distance_(0) {
 }
 
 EdgeEffect::~EdgeEffect() { }
@@ -173,8 +193,8 @@ bool EdgeEffect::IsFinished() const {
 }
 
 void EdgeEffect::Finish() {
-  DisableLayer(edge_.get());
-  DisableLayer(glow_.get());
+  edge_->Disable();
+  glow_->Disable();
   pull_distance_ = 0;
   state_ = STATE_IDLE;
 }
@@ -359,8 +379,8 @@ void EdgeEffect::ApplyToLayers(gfx::SizeF window_size,
   // An empty window size, while meaningless, is also relatively harmless, and
   // will simply prevent any drawing of the layers.
   if (window_size.IsEmpty()) {
-    DisableLayer(edge_.get());
-    DisableLayer(glow_.get());
+    edge_->Disable();
+    glow_->Disable();
     return;
   }
 
@@ -368,13 +388,26 @@ void EdgeEffect::ApplyToLayers(gfx::SizeF window_size,
   const int scaled_glow_height = static_cast<int>(
       std::min(glow_height * glow_scale_y_ * kGlowHeightToWidthRatio * 0.6f,
                glow_height * kMaxGlowHeight) + 0.5f);
-  UpdateLayer(
-      glow_.get(), edge, window_size, offset, scaled_glow_height, glow_alpha_);
+  glow_->Update(edge, window_size, offset, scaled_glow_height, glow_alpha_);
 
   // Edge
- const int scaled_edge_height = static_cast<int>(edge_height * edge_scale_y_);
-  UpdateLayer(
-      edge_.get(), edge, window_size, offset, scaled_edge_height, edge_alpha_);
+  const int scaled_edge_height = static_cast<int>(edge_height * edge_scale_y_);
+  edge_->Update(edge, window_size, offset, scaled_edge_height, edge_alpha_);
+}
+
+void EdgeEffect::SetParent(cc::Layer* parent) {
+  edge_->SetParent(parent);
+  glow_->SetParent(parent);
+}
+
+// static
+void EdgeEffect::PreloadResources(
+    ui::SystemUIResourceManager* resource_manager) {
+  DCHECK(resource_manager);
+  resource_manager->PreloadResource(
+      ui::SystemUIResourceManager::OVERSCROLL_EDGE);
+  resource_manager->PreloadResource(
+      ui::SystemUIResourceManager::OVERSCROLL_GLOW);
 }
 
 } // namespace content