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..992a129cabdde61df04939c46d4e2bf21b774576 100644
--- a/content/browser/android/edge_effect.cc
+++ b/content/browser/android/edge_effect.cc
@@ -5,6 +5,9 @@
 #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_layer.h"
+#include "ui/base/android/system_ui_resource_manager.h"
 
 namespace content {
 
@@ -141,29 +144,75 @@ void UpdateLayer(cc::Layer* layer,
   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) {
+}  // namespace
+
+class EdgeEffect::EffectLayer : public ui::SystemUIResourceLayer {
+ public:
+  static scoped_ptr<EffectLayer> Create(
+      ui::SystemUIResourceManager::Type type,
+      ui::SystemUIResourceManager* resource_manager) {
+    return make_scoped_ptr(new EffectLayer(type, resource_manager));
+  }
+
+  virtual ~EffectLayer() {
+    resource_manager_->Unsubscribe(type_, this);
+    ui_resource_layer_->RemoveFromParent();
+  }
+
+  // ui::SystemUIResourceLayer implementation.
+  virtual void SetUIResourceId(cc::UIResourceId id) OVERRIDE {
+    ui_resource_id_ = id;
+    ui_resource_layer_->SetUIResourceId(id);
+  }
+
+  cc::Layer* layer() { return ui_resource_layer_.get(); }
+
+  void SetParent(cc::Layer* parent) {
+    if (ui_resource_layer_->parent() != parent)
+      parent->AddChild(ui_resource_layer_);

[jdduke (slow), 2014/07/28 20:45:38]

Do we need a null check on |parent|? Otherwise we should DCHECK.

+    ui_resource_layer_->SetUIResourceId(ui_resource_id_);
+  }
+
+ private:
+  EffectLayer(ui::SystemUIResourceManager::Type type,
+               ui::SystemUIResourceManager* resource_manager)
+      : ui_resource_id_(0),
+        ui_resource_layer_(cc::UIResourceLayer::Create()),
+        type_(type),
+        resource_manager_(resource_manager) {
+    resource_manager_->Subscribe(type_, this);
+  }
+
+  cc::UIResourceId ui_resource_id_;
+  scoped_refptr<cc::UIResourceLayer> ui_resource_layer_;
+  ui::SystemUIResourceManager::Type type_;
+  ui::SystemUIResourceManager* resource_manager_;
+
+  DISALLOW_COPY_AND_ASSIGN(EffectLayer);
+};
+
+EdgeEffect::EdgeEffect(ui::SystemUIResourceManager* 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) {
+  edge_ = EffectLayer::Create(ui::SystemUIResourceManager::OVERSCROLL_EDGE,
+                              resource_manager);
+  glow_ = EffectLayer::Create(ui::SystemUIResourceManager::OVERSCROLL_GLOW,
+                              resource_manager);
   // Prevent the provided layers from drawing until the effect is activated.
-  DisableLayer(edge_.get());
-  DisableLayer(glow_.get());
+  DisableLayer(edge_->layer());
+  DisableLayer(glow_->layer());
 }
 
 EdgeEffect::~EdgeEffect() { }
@@ -173,8 +222,8 @@ bool EdgeEffect::IsFinished() const {
 }
 
 void EdgeEffect::Finish() {
-  DisableLayer(edge_.get());
-  DisableLayer(glow_.get());
+  DisableLayer(edge_->layer());
+  DisableLayer(glow_->layer());
   pull_distance_ = 0;
   state_ = STATE_IDLE;
 }
@@ -359,8 +408,8 @@ 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());
+    DisableLayer(edge_->layer());
+    DisableLayer(glow_->layer());
     return;
   }
 
@@ -368,13 +417,26 @@ 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_);
+  UpdateLayer(glow_->layer(),
+              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_);
+  UpdateLayer(edge_->layer(),
+              edge,
+              window_size,
+              offset,
+              scaled_edge_height,
+              edge_alpha_);
+}
+
+void EdgeEffect::SetParent(cc::Layer* parent) {
+  edge_->SetParent(parent);
+  glow_->SetParent(parent);
 }
 
 } // namespace content