Revert 129925 - ash: Icon cache for app list to save shadow generation time.

- Add an IconCache that stores processed (resized and shadow-generated) image,
  keyed by source image + desired size;
- The cache is created with AppList controller and destroyed when controller is
  gone;
- Controller marks all entries in cache unused before showing the UI and purges
  all unused entry after dismissing UI;
- In item view, try cache first to get processed image before scheduling job,
  and update cache when background processing comes back;

BUG=120961
TEST=Verify fix for issue 120961.


Review URL: http://codereview.chromium.org/9934006

TBR=xiyuan@chromium.org
Review URL: https://chromiumcodereview.appspot.com/9959039

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@129931 0039d316-1c4b-4281-b951-d872f2087c98

4 files changed, 9 insertions, 167 deletions

diff --git a/ash/app_list/app_list.cc b/ash/app_list/app_list.cc
index b8b4741..6972eb0 100644
--- a/ash/app_list/app_list.cc
+++ b/ash/app_list/app_list.cc
@@ -5,7 +5,6 @@
 #include "ash/app_list/app_list.h"
 
 #include "ash/app_list/app_list_view.h"
-#include "ash/app_list/icon_cache.h"
 #include "ash/shell_delegate.h"
 #include "ash/shell.h"
 #include "ash/shell_window_ids.h"
@@ -47,12 +46,10 @@ ui::Layer* GetLayer(views::Widget* widget) {
 // AppList, public:
 
 AppList::AppList() : is_visible_(false), view_(NULL) {
-  IconCache::CreateInstance();
 }
 
 AppList::~AppList() {
   ResetView();
-  IconCache::DeleteInstance();
 }
 
 void AppList::SetVisible(bool visible) {
@@ -83,8 +80,6 @@ void AppList::SetView(AppListView* view) {
   DCHECK(view_ == NULL);
 
   if (is_visible_) {
-    IconCache::GetInstance()->MarkAllEntryUnused();
-
     view_ = view;
     views::Widget* widget = view_->GetWidget();
     widget->AddObserver(this);
@@ -110,8 +105,6 @@ void AppList::ResetView() {
   Shell::GetInstance()->RemoveRootWindowEventFilter(this);
   widget->GetNativeView()->GetRootWindow()->RemoveRootWindowObserver(this);
   view_ = NULL;
-
-  IconCache::GetInstance()->PurgeAllUnused();
 }
 
 void AppList::ScheduleAnimation() {
diff --git a/ash/app_list/app_list_item_view.cc b/ash/app_list/app_list_item_view.cc
index 5addda1..ec7594b 100644
--- a/ash/app_list/app_list_item_view.cc
+++ b/ash/app_list/app_list_item_view.cc
@@ -7,7 +7,6 @@
 #include "ash/app_list/app_list_item_model.h"
 #include "ash/app_list/app_list_model_view.h"
 #include "ash/app_list/drop_shadow_label.h"
-#include "ash/app_list/icon_cache.h"
 #include "base/bind.h"
 #include "base/message_loop.h"
 #include "base/synchronization/cancellation_flag.h"
@@ -261,20 +260,15 @@ void AppListItemView::UpdateIcon() {
 
   CancelPendingIconOperation();
 
-  SkBitmap shadow;
-  if (IconCache::GetInstance()->Get(icon, icon_size_, &shadow)) {
-    icon_->SetImage(shadow);
-  } else {
-    // Schedule resize and shadow generation.
-    icon_op_ = new IconOperation(icon, icon_size_);
-    base::WorkerPool::PostTaskAndReply(
-        FROM_HERE,
-        base::Bind(&IconOperation::Run, icon_op_),
-        base::Bind(&AppListItemView::ApplyShadow,
-                   apply_shadow_factory_.GetWeakPtr(),
-                   icon_op_),
-        true /* task_is_slow */);
-  }
+  // Schedule resize and shadow generation.
+  icon_op_ = new IconOperation(icon, icon_size_);
+  base::WorkerPool::PostTaskAndReply(
+      FROM_HERE,
+      base::Bind(&IconOperation::Run, icon_op_),
+      base::Bind(&AppListItemView::ApplyShadow,
+                 apply_shadow_factory_.GetWeakPtr(),
+                 icon_op_),
+      true /* task_is_slow */);
 }
 
 void AppListItemView::CancelPendingIconOperation() {
@@ -288,7 +282,6 @@ void AppListItemView::CancelPendingIconOperation() {
 
 void AppListItemView::ApplyShadow(scoped_refptr<IconOperation> op) {
   icon_->SetImage(op->bitmap());
-  IconCache::GetInstance()->Put(model_->icon(), icon_size_, op->bitmap());
 
   DCHECK(op.get() == icon_op_.get());
   icon_op_ = NULL;
diff --git a/ash/app_list/icon_cache.cc b/ash/app_list/icon_cache.cc
deleted file mode 100644
index dcd295c..0000000
--- a/ash/app_list/icon_cache.cc
+++ /dev/null
@@ -1,87 +0,0 @@
-// Copyright (c) 2012 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 "ash/app_list/icon_cache.h"
-
-#include "base/logging.h"
-#include "base/md5.h"
-#include "ui/gfx/size.h"
-
-namespace {
-
-// Gets cache key based on |image| contents and desired |size|.
-std::string GetKey(const SkBitmap& image, const gfx::Size& size) {
-  SkAutoLockPixels image_lock(image);
-  base::MD5Digest digest;
-  MD5Sum(image.getPixels(), image.getSize(), &digest);
-
-  return MD5DigestToBase16(digest) + "." + size.ToString();
-}
-
-}  // namespace
-
-namespace ash {
-
-// static
-IconCache* IconCache::instance_ = NULL;
-
-// static
-void IconCache::CreateInstance() {
-  DCHECK(!instance_);
-  instance_ = new IconCache;
-}
-
-// static
-void IconCache::DeleteInstance() {
-  DCHECK(instance_);
-  delete instance_;
-  instance_ = NULL;
-}
-
-// static
-IconCache* IconCache::GetInstance() {
-  DCHECK(instance_);
-  return instance_;
-}
-
-void IconCache::MarkAllEntryUnused() {
-  for (Cache::iterator i = cache_.begin(); i != cache_.end(); ++i)
-    i->second.used = false;
-}
-
-void IconCache::PurgeAllUnused() {
-  for (Cache::iterator i = cache_.begin(); i != cache_.end();) {
-    Cache::iterator current(i);
-    ++i;
-    if (!current->second.used)
-      cache_.erase(current);
-  }
-}
-
-bool IconCache::Get(const SkBitmap& src,
-                    const gfx::Size& size,
-                    SkBitmap* processed) {
-  Cache::iterator it = cache_.find(GetKey(src, size));
-  if (it == cache_.end())
-    return false;
-
-  it->second.used = true;
-
-  if (processed)
-    *processed = it->second.image;
-  return true;
-}
-
-void IconCache::Put(const SkBitmap& src,
-                    const gfx::Size& size,
-                    const SkBitmap& processed) {
-  const std::string key = GetKey(src, size);
-  cache_[key].image = processed;
-  cache_[key].used = true;
-}
-
-IconCache::IconCache() {
-}
-
-}  // namespace ash
diff --git a/ash/app_list/icon_cache.h b/ash/app_list/icon_cache.h
deleted file mode 100644
index e0af324..0000000
--- a/ash/app_list/icon_cache.h
+++ /dev/null
@@ -1,57 +0,0 @@
-// Copyright (c) 2012 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.
-
-#ifndef ASH_APP_LIST_ICON_CACHE_H_
-#define ASH_APP_LIST_ICON_CACHE_H_
-#pragma once
-
-#include <map>
-#include <string>
-
-#include "base/basictypes.h"
-#include "third_party/skia/include/core/SkBitmap.h"
-
-namespace gfx {
-class Size;
-}
-
-namespace ash {
-
-// IconCache stores processed image, keyed by the source image and desired size.
-class IconCache {
- public:
-  static void CreateInstance();
-  static void DeleteInstance();
-
-  static IconCache* GetInstance();
-
-  void MarkAllEntryUnused();
-  void PurgeAllUnused();
-
-  bool Get(const SkBitmap& src,
-           const gfx::Size& size,
-           SkBitmap* processed);
-  void Put(const SkBitmap& src,
-           const gfx::Size& size,
-           const SkBitmap& processed);
-
- private:
-  struct Item {
-    SkBitmap image;
-    bool used;
-  };
-  typedef std::map<std::string, Item> Cache;
-
-  IconCache();
-
-  static IconCache* instance_;
-
-  Cache cache_;
-
-  DISALLOW_COPY_AND_ASSIGN(IconCache);
-};
-
-}  // namespace ash
-
-#endif  // ASH_APP_LIST_ICON_CACHE_H_