android: add ThumbnailCache

chrome/browser/android/thumbnail/thumbnail.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 "base/logging.h"
+#include "chrome/browser/android/thumbnail/thumbnail.h"
+#include "content/public/browser/android/ui_resource_provider.h"
+#include "third_party/skia/include/core/SkBitmap.h"
+#include "third_party/skia/include/core/SkCanvas.h"
+#include "ui/gfx/geometry/size_conversions.h"
+
+namespace {
+
+SkBitmap CreateSmallHolderBitmap() {
+  SkBitmap small_bitmap;
+  SkCanvas canvas(small_bitmap);
+  small_bitmap.allocPixels(
+      SkImageInfo::Make(1, 1, kRGBA_8888_SkColorType, kOpaque_SkAlphaType));
+  canvas.drawColor(SK_ColorWHITE);
+  small_bitmap.setImmutable();
+  return small_bitmap;
+}
+
+}  // anonymous namespace
+
+scoped_ptr<Thumbnail> Thumbnail::Create(
+    TabId tab_id,
+    const base::Time& time_stamp,
+    float scale,
+    content::UIResourceProvider* ui_resource_provider,
+    ThumbnailDelegate* thumbnail_delegate) {
+  return make_scoped_ptr(new Thumbnail(
+      tab_id, time_stamp, scale, ui_resource_provider, thumbnail_delegate));
+}
+
+Thumbnail::Thumbnail(TabId tab_id,
+                     const base::Time& time_stamp,
+                     float scale,
+                     content::UIResourceProvider* ui_resource_provider,
+                     ThumbnailDelegate* thumbnail_delegate)
+    : tab_id_(tab_id),
+      time_stamp_(time_stamp),
+      scale_(scale),
+      bitmap_(gfx::Size(1, 1), true),
+      ui_resource_id_(0),
+      retrieved_(false),
+      ui_resource_provider_(ui_resource_provider),
+      thumbnail_delegate_(thumbnail_delegate) {
+}
+
+Thumbnail::~Thumbnail() {
+  ClearUIResourceId();
+}
+
+void Thumbnail::SetBitmap(const SkBitmap& bitmap) {
+  DCHECK(!bitmap.empty());
+  ClearUIResourceId();
+  scaled_content_size_ =
+      gfx::ScaleSize(gfx::Size(bitmap.width(), bitmap.height()), 1.f / scale_);
+  scaled_data_size_ = scaled_content_size_;
+  bitmap_ = cc::UIResourceBitmap(bitmap);
+}
+
+void Thumbnail::SetCompressedBitmap(skia::RefPtr<SkPixelRef> compressed_bitmap,
+                                    const gfx::Size& content_size) {
+  DCHECK(compressed_bitmap);
+  DCHECK(!content_size.IsEmpty());
+  ClearUIResourceId();
+  gfx::Size data_size(compressed_bitmap->info().width(),
+                      compressed_bitmap->info().height());
+  scaled_content_size_ = gfx::ScaleSize(content_size, 1.f / scale_);
+  scaled_data_size_ = gfx::ScaleSize(data_size, 1.f / scale_);
+  bitmap_ = cc::UIResourceBitmap(compressed_bitmap, data_size);
+}
+
+void Thumbnail::CreateUIResource() {
+  DCHECK(ui_resource_provider_);
+  if (!ui_resource_id_)
+    ui_resource_id_ = ui_resource_provider_->CreateUIResource(this);
+}
+
+cc::UIResourceBitmap Thumbnail::GetBitmap(cc::UIResourceId uid,
+                                          bool resource_lost) {
+  if (retrieved_)
+    return bitmap_;
+
+  retrieved_ = true;
+
+  cc::UIResourceBitmap old_bitmap(bitmap_);
+  // Return a place holder for all other calls to GetBitmap.
+  bitmap_ = cc::UIResourceBitmap(CreateSmallHolderBitmap());
+  return old_bitmap;
+}
+
+void Thumbnail::UIResourceIsInvalid() {
+  ui_resource_id_ = 0;
+  if (thumbnail_delegate_)
+    thumbnail_delegate_->InvalidateCachedThumbnail(this);
+}
+
+void Thumbnail::ClearUIResourceId() {
+  if (ui_resource_id_ && ui_resource_provider_)
+    ui_resource_provider_->DeleteUIResource(ui_resource_id_);
+  ui_resource_id_ = 0;
+}