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 "third_party/skia/include/core/SkBitmap.h"
+#include "ui/base/android/system_ui_resource_layer.h"
+#include "ui/base/android/ui_resource_client_android.h"
+#include "ui/base/android/ui_resource_provider.h"
+#include "ui/gfx/android/java_bitmap.h"
+
+namespace content {
+
+SystemUIResourceManagerImpl::SystemUIResourceManagerImpl(
+    ui::UIResourceProvider* ui_resource_provider)
+    : ui_resource_provider_(ui_resource_provider), weak_factory_(this) {
+}
+
+void SystemUIResourceManagerImpl::Subscribe(
+    ui::SystemUIResourceManager::Type type,
+    ui::SystemUIResourceLayer* layer) {
+  DCHECK(layer);
+  GetData(type)->Subscribe(layer);
+}
+
+void SystemUIResourceManagerImpl::Unsubscribe(
+    ui::SystemUIResourceManager::Type type,
+    ui::SystemUIResourceLayer* layer) {
+  DCHECK(layer);
+  GetData(type)->Unsubscribe(layer);
+}
+
+void SystemUIResourceManagerImpl::RefreshResourceOnSubscribers(
+    ui::SystemUIResourceManager::Type type) {
+  GetData(type)->RefreshResource();
+}
+
+SystemUIResourceManagerImpl::Data* SystemUIResourceManagerImpl::GetData(
+    ui::SystemUIResourceManager::Type type) {
+  SystemUIResourceMap::iterator iter = resource_map_.find(type);
+  if (iter == resource_map_.end()) {
+    scoped_ptr<Data> resource_data = make_scoped_ptr(new Data());
+    resource_map_.set(type, resource_data.Pass());
+
+    // Lazily build the resource.
+    BuildResource(type);
+  }
+  return resource_map_.get(type);
+}
+
+void SystemUIResourceManagerImpl::BuildResource(
+    ui::SystemUIResourceManager::Type type) {
+  if (GetData(type)->HasResource())

[jdduke (slow), 2014/07/16 19:01:51]

Should this be DCHECK(!GetData(type)->HasResource());

[powei, 2014/07/16 23:33:51]

Done.

+    return;
+
+  // 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_);
+  GetData(type)->SetResource(resource.Pass());
+}
+
+SystemUIResourceManagerImpl::Data::Data() {
+}
+
+SystemUIResourceManagerImpl::Data::~Data() {
+  if (resource_)
+    resource_->SetClient(NULL);
+}
+
+void SystemUIResourceManagerImpl::Data::Subscribe(
+    ui::SystemUIResourceLayer* layer) {
+  DCHECK(layer);
+  if (resource_)
+    layer->SetUIResourceId(resource_->id());
+
+  if (!subscribers_.HasObserver(layer))
+    subscribers_.AddObserver(layer);
+}
+
+void SystemUIResourceManagerImpl::Data::Unsubscribe(
+    ui::SystemUIResourceLayer* layer) {
+  DCHECK(layer);
+  layer->SetUIResourceId(0);
+  subscribers_.RemoveObserver(layer);
+}
+
+void SystemUIResourceManagerImpl::Data::SetResource(
+    scoped_ptr<SystemUIResource> resource) {
+  DCHECK(resource);

[jdduke (slow), 2014/07/16 19:01:51]

also DCHECK(!resource_)?

[powei, 2014/07/16 23:33:51]

Done.

+  resource_ = resource.Pass();
+  resource_->SetClient(this);
+
+  RefreshResource();
+}
+
+void SystemUIResourceManagerImpl::Data::RefreshResource() {
+  if (!resource_)
+    return;
+
+  resource_->Load();
+  FOR_EACH_OBSERVER(ui::SystemUIResourceLayer,

[jdduke (slow), 2014/07/16 19:01:51]

Shouldn't the loading trigger a call to |OnUIResourceIdChanged()| only if its
necessary? Pushing the ID on every subscriber seems unfortunate if we can avoid
it?

[powei, 2014/07/16 23:33:51]

Done.  Now this only happens when the LTH returns.

+                    subscribers_,
+                    SetUIResourceId(resource_->id()));
+}
+
+void SystemUIResourceManagerImpl::Data::OnUIResourceIdChanged() {
+  DCHECK(resource_);
+
+  FOR_EACH_OBSERVER(ui::SystemUIResourceLayer,
+                    subscribers_,
+                    SetUIResourceId(resource_->id()));
+}
+
+}  // namespace content