[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/observer_list.h"
+#include "base/threading/worker_pool.h"
+#include "cc/resources/ui_resource_bitmap.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/gfx/android/java_bitmap.h"
+
+namespace content {
+
+class SystemUIResourceManagerImpl::Entry
+    : public content::UIResourceClientAndroid {
+ public:
+  explicit Entry(UIResourceProvider* provider) : id_(0), provider_(provider) {
+    DCHECK(provider);
+  }
+
+  virtual ~Entry() {
+    if (id_)
+      provider_->DeleteUIResource(id_);
+    id_ = 0;
+  }
+
+  void SetBitmap(const SkBitmap& bitmap) {
+    DCHECK(bitmap_.empty());
+    DCHECK(!bitmap.empty());
+    DCHECK(!id_);
+    bitmap_ = bitmap;
+  }
+
+  cc::UIResourceId GetUIResourceId() {
+    if (bitmap_.empty())
+      return 0;
+    if (!id_)
+      id_ = provider_->CreateUIResource(this);
+    return id_;
+  }
+
+  // content::UIResourceClient implementation.
+  virtual cc::UIResourceBitmap GetBitmap(cc::UIResourceId uid,
+                                         bool resource_lost) OVERRIDE {
+    DCHECK(!bitmap_.empty());
+    return cc::UIResourceBitmap(bitmap_);
+  }
+
+  // content::UIResourceClientAndroid implementation.
+  virtual void UIResourceIsInvalid() OVERRIDE { id_ = 0; }
+
+  const SkBitmap& bitmap() const { return bitmap_; }
+
+ private:
+  SkBitmap bitmap_;
+  cc::UIResourceId id_;
+  UIResourceProvider* provider_;
+
+  DISALLOW_COPY_AND_ASSIGN(Entry);
+};
+
+SystemUIResourceManagerImpl::SystemUIResourceManagerImpl(
+    UIResourceProvider* ui_resource_provider)
+    : ui_resource_provider_(ui_resource_provider), weak_factory_(this) {
+}
+
+SystemUIResourceManagerImpl::~SystemUIResourceManagerImpl() {
+}
+
+void SystemUIResourceManagerImpl::PreloadResource(ResourceType type) {
+  GetEntry(type);
+}
+
+cc::UIResourceId SystemUIResourceManagerImpl::GetUIResourceId(
+    ResourceType type) {
+  return GetEntry(type)->GetUIResourceId();
+}
+
+SystemUIResourceManagerImpl::Entry* SystemUIResourceManagerImpl::GetEntry(
+    ResourceType type) {
+  DCHECK_GE(type, RESOURCE_TYPE_FIRST);
+  DCHECK_LE(type, RESOURCE_TYPE_LAST);
+  if (!resource_map_[type]) {
+    resource_map_[type].reset(new Entry(ui_resource_provider_));
+    // Lazily build the resource.
+    BuildResource(type);
+  }
+  return resource_map_[type].get();
+}
+
+void SystemUIResourceManagerImpl::BuildResource(ResourceType type) {
+  DCHECK(GetEntry(type)->bitmap().empty());
+
+  // 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(ResourceType 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(
+    ResourceType type,
+    SkBitmap* bitmap_holder) {
+  DCHECK(bitmap_holder);
+  GetEntry(type)->SetBitmap(*bitmap_holder);
+}
+
+}  // namespace content