android: Use UIResource for overscroll glow

content/browser/android/system_ui_resource_manager_impl.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/system_ui_resource_manager_impl.h"
+
+#include "base/bind.h"
+#include "base/bind_helpers.h"
+#include "base/location.h"
+#include "base/threading/worker_pool.h"
+#include "cc/resources/ui_resource_bitmap.h"
+#include "content/browser/android/system_ui_resource.h"
+#include "content/public/browser/android/ui_resource_client_android.h"
+#include "content/public/browser/android/ui_resource_provider.h"
+#include "third_party/skia/include/core/SkBitmap.h"
+#include "ui/base/android/system_ui_resource_layer.h"
+#include "ui/gfx/android/java_bitmap.h"
+
+namespace content {
+
+class SystemUIResourceManagerImpl::Entry : public SystemUIResourceClient {
+ public:
+  Entry() {}
+  virtual ~Entry() {
+    if (resource_)
+      resource_->SetClient(NULL);
+  }
+  void Subscribe(ui::SystemUIResourceLayer* layer) {
+    DCHECK(layer);
+    if (resource_)
+      layer->SetUIResourceId(resource_->id());
+
+    if (!subscribers_.HasObserver(layer))
+      subscribers_.AddObserver(layer);
+  }
+
+  void Unsubscribe(ui::SystemUIResourceLayer* layer) {
+    DCHECK(layer);
+    layer->SetUIResourceId(0);
+    subscribers_.RemoveObserver(layer);
+  }
+
+  void SetResource(scoped_ptr<SystemUIResource> resource) {
+    DCHECK(resource);
+    DCHECK(!resource_);
+    resource_ = resource.Pass();
+    resource_->SetClient(this);
+    RefreshResource();
+  }
+
+  void RefreshResource() {
+    if (!resource_)
+      return;
+    resource_->Load();
+    FOR_EACH_OBSERVER(ui::SystemUIResourceLayer,
+                      subscribers_,
+                      SetUIResourceId(resource_->id()));
+  }
+
+  bool HasResource() { return resource_; }
+
+  // Implements SystemUIResourceClient.
+  virtual void OnUIResourceIdChanged() OVERRIDE {
+    DCHECK(resource_);
+    FOR_EACH_OBSERVER(ui::SystemUIResourceLayer,
+                      subscribers_,
+                      SetUIResourceId(resource_->id()));
+  }
+
+ private:
+  typedef ObserverList<ui::SystemUIResourceLayer> Subscribers;
+  scoped_ptr<SystemUIResource> resource_;
+  Subscribers subscribers_;
+
+  DISALLOW_COPY_AND_ASSIGN(Entry);
+};
+
+SystemUIResourceManagerImpl::SystemUIResourceManagerImpl(
+    UIResourceProvider* ui_resource_provider)
+    : ui_resource_provider_(ui_resource_provider), weak_factory_(this) {
+}
+
+SystemUIResourceManagerImpl::~SystemUIResourceManagerImpl() {
+}
+
+void SystemUIResourceManagerImpl::Subscribe(
+    ui::SystemUIResourceManager::Type type,
+    ui::SystemUIResourceLayer* layer) {
+  DCHECK(layer);
+  GetEntry(type)->Subscribe(layer);
+}
+
+void SystemUIResourceManagerImpl::Unsubscribe(
+    ui::SystemUIResourceManager::Type type,
+    ui::SystemUIResourceLayer* layer) {
+  DCHECK(layer);
+  GetEntry(type)->Unsubscribe(layer);
+}
+
+void SystemUIResourceManagerImpl::RefreshResources() {
+  GetEntry(ui::SystemUIResourceManager::OVERSCROLL_GLOW)->RefreshResource();
+  GetEntry(ui::SystemUIResourceManager::OVERSCROLL_EDGE)->RefreshResource();
+}
+
+SystemUIResourceManagerImpl::Entry* SystemUIResourceManagerImpl::GetEntry(
+    ui::SystemUIResourceManager::Type type) {
+  SystemUIResourceMap::iterator iter = resource_map_.find(type);
+  if (iter == resource_map_.end()) {
+    scoped_ptr<Entry> resource_entry = make_scoped_ptr(new Entry());
+    resource_map_.set(type, resource_entry.Pass());
+
+    // Lazily build the resource.
+    BuildResource(type);
+  }
+  return resource_map_.get(type);
+}
+
+void SystemUIResourceManagerImpl::BuildResource(
+    ui::SystemUIResourceManager::Type type) {
+  DCHECK(!GetEntry(type)->HasResource());
+
+  // Instead of blocking the main thread, we post a task to load the bitmap.
+  SkBitmap* bitmap = new SkBitmap();
+  base::Closure load_bitmap =
+      base::Bind(&SystemUIResourceManagerImpl::LoadBitmap, type, bitmap);
+  base::Closure finished_load =
+      base::Bind(&SystemUIResourceManagerImpl::OnFinishedLoadBitmap,
+                 weak_factory_.GetWeakPtr(),
+                 type,
+                 base::Owned(bitmap));
+  base::WorkerPool::PostTaskAndReply(
+      FROM_HERE, load_bitmap, finished_load, true);
+}
+
+void SystemUIResourceManagerImpl::LoadBitmap(
+    ui::SystemUIResourceManager::Type type,
+    SkBitmap* bitmap_holder) {
+  SkBitmap bitmap;
+  switch (type) {
+    case ui::SystemUIResourceManager::OVERSCROLL_EDGE:
+      bitmap = gfx::CreateSkBitmapFromAndroidResource(
+          "android:drawable/overscroll_edge", gfx::Size(128, 12));
+      break;
+    case ui::SystemUIResourceManager::OVERSCROLL_GLOW:
+      bitmap = gfx::CreateSkBitmapFromAndroidResource(
+          "android:drawable/overscroll_glow", gfx::Size(128, 64));
+      break;
+  }
+  bitmap.setImmutable();
+  *bitmap_holder = bitmap;
+}
+
+void SystemUIResourceManagerImpl::OnFinishedLoadBitmap(
+    ui::SystemUIResourceManager::Type type,
+    SkBitmap* bitmap_holder) {
+  scoped_ptr<SystemUIResource> resource =
+      SystemUIResource::Create(*bitmap_holder, ui_resource_provider_);
+  GetEntry(type)->SetResource(resource.Pass());
+}
+
+} // namespace content