Modified ThumbnailStore to cache/store JPEGs instead

of SkBitmaps.

Add command line flag "--thumbnail-store" to enable
using the ThumbnailStore facility instead of the current
ThumbnailDatabase.

Original review: http://codereview.chromium.org/118409
Patch by Meelap Shah

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@17971 0039d316-1c4b-4281-b951-d872f2087c98

13 files changed, 185 insertions, 124 deletions

diff --git a/chrome/browser/browser.vcproj b/chrome/browser/browser.vcproj
index b20ce97..c6bbe8b 100644
--- a/chrome/browser/browser.vcproj
+++ b/chrome/browser/browser.vcproj
@@ -2805,6 +2805,14 @@
 			>

 		</File>

 		<File

+			RelativePath=".\thumbnail_store.cc"

+			>

+		</File>

+		<File

+			RelativePath=".\thumbnail_store.h"

+			>

+		</File>

+		<File

 			RelativePath=".\toolbar_model.cc"

 			>

 		</File>

diff --git a/chrome/browser/dom_ui/dom_ui_thumbnail_source.cc b/chrome/browser/dom_ui/dom_ui_thumbnail_source.cc
index df9c675..9f3d175 100644
--- a/chrome/browser/dom_ui/dom_ui_thumbnail_source.cc
+++ b/chrome/browser/dom_ui/dom_ui_thumbnail_source.cc
@@ -5,10 +5,15 @@
 #include "chrome/browser/dom_ui/dom_ui_thumbnail_source.h"
 
 #include "app/resource_bundle.h"
+#include "base/command_line.h"
+#include "base/gfx/jpeg_codec.h"
 #include "chrome/browser/profile.h"
+#include "chrome/browser/thumbnail_store.h"
+#include "chrome/common/chrome_switches.h"
 #include "chrome/common/url_constants.h"
 #include "googleurl/src/gurl.h"
 #include "grit/theme_resources.h"
+#include "third_party/skia/include/core/SkBitmap.h"
 
 DOMUIThumbnailSource::DOMUIThumbnailSource(Profile* profile)
     : DataSource(chrome::kChromeUIThumbnailPath, MessageLoop::current()),
@@ -17,6 +22,23 @@ DOMUIThumbnailSource::DOMUIThumbnailSource(Profile* profile)
 
 void DOMUIThumbnailSource::StartDataRequest(const std::string& path,
                                             int request_id) {
+  if (CommandLine::ForCurrentProcess()->HasSwitch(switches::kThumbnailStore)) {
+    ThumbnailStore* store = profile_->GetThumbnailStore();
+    RefCountedBytes* data = NULL;
+
+    if (!store->GetPageThumbnail(GURL(path), &data)) {
+      if (!default_thumbnail_.get()) {
+        default_thumbnail_ = new RefCountedBytes;
+        ResourceBundle::GetSharedInstance().LoadImageResourceBytes(
+            IDR_DEFAULT_THUMBNAIL, &default_thumbnail_->data);
+      }
+      SendResponse(request_id, default_thumbnail_);
+      return;
+    }
+    SendResponse(request_id, data);
+    return;
+  }
+
   HistoryService* hs = profile_->GetHistoryService(Profile::EXPLICIT_ACCESS);
   if (hs) {
     HistoryService::Handle handle = hs->GetPageThumbnail(
diff --git a/chrome/browser/profile.cc b/chrome/browser/profile.cc
index f493a42..b7bd98d 100644
--- a/chrome/browser/profile.cc
+++ b/chrome/browser/profile.cc
@@ -28,6 +28,7 @@
 #include "chrome/browser/sessions/tab_restore_service.h"
 #include "chrome/browser/spellchecker.h"
 #include "chrome/browser/ssl/ssl_host_state.h"
+#include "chrome/browser/thumbnail_store.h"
 #include "chrome/browser/browser_theme_provider.h"
 #include "chrome/browser/visitedlink_master.h"
 #include "chrome/browser/webdata/web_data_service.h"
@@ -343,6 +344,10 @@ class OffTheRecordProfileImpl : public Profile,
     return profile_->GetSpellChecker();
   }
 
+  virtual ThumbnailStore* GetThumbnailStore() {
+    return NULL;
+  }
+
   virtual void MarkAsCleanShutdown() {
   }
 
@@ -926,6 +931,14 @@ TabRestoreService* ProfileImpl::GetTabRestoreService() {
   return tab_restore_service_.get();
 }
 
+ThumbnailStore* ProfileImpl::GetThumbnailStore() {
+  if (!thumbnail_store_.get()) {
+    thumbnail_store_ = new ThumbnailStore;
+    thumbnail_store_->Init(GetPath().AppendASCII("thumbnailstore\\"));
+  }
+  return thumbnail_store_.get();
+}
+
 void ProfileImpl::ResetTabRestoreService() {
   tab_restore_service_ = NULL;
 }
diff --git a/chrome/browser/profile.h b/chrome/browser/profile.h
index d5e800f..0c6179e 100644
--- a/chrome/browser/profile.h
+++ b/chrome/browser/profile.h
@@ -24,6 +24,7 @@ namespace net {
 class ForceTLSState;
 }
 class BookmarkModel;
+class BrowserThemeProvider;
 class ChromeURLRequestContext;
 class DownloadManager;
 class Extension;
@@ -40,7 +41,7 @@ class SQLitePersistentCookieStore;
 class TabRestoreService;
 class TemplateURLFetcher;
 class TemplateURLModel;
-class BrowserThemeProvider;
+class ThumbnailStore;
 class URLRequestContext;
 class UserScriptMaster;
 class VisitedLinkMaster;
@@ -190,6 +191,8 @@ class Profile {
   // Returns or creates the ThemeProvider associated with this profile
   virtual ThemeProvider* GetThemeProvider() = 0;
 
+  virtual ThumbnailStore* GetThumbnailStore() = 0;
+
   // Returns the request context information associated with this profile.  Call
   // this only on the UI thread, since it can send notifications that should
   // happen on the UI thread.
@@ -327,6 +330,7 @@ class ProfileImpl : public Profile,
   virtual void SetTheme(Extension* extension);
   virtual void ClearTheme();
   virtual ThemeProvider* GetThemeProvider();
+  virtual ThumbnailStore* GetThumbnailStore();
   virtual bool HasCreatedDownloadManager() const;
   virtual URLRequestContext* GetRequestContext();
   virtual URLRequestContext* GetRequestContextForMedia();
@@ -391,6 +395,7 @@ class ProfileImpl : public Profile,
   scoped_ptr<SSLHostState> ssl_host_state_;
   scoped_ptr<net::ForceTLSState> force_tls_state_;
   scoped_ptr<PrefService> prefs_;
+  scoped_refptr<ThumbnailStore> thumbnail_store_;
   scoped_ptr<TemplateURLFetcher> template_url_fetcher_;
   scoped_ptr<TemplateURLModel> template_url_model_;
   scoped_ptr<BookmarkModel> bookmark_bar_model_;
diff --git a/chrome/browser/tab_contents/tab_contents.cc b/chrome/browser/tab_contents/tab_contents.cc
index db21d93..a39f7eb 100644
--- a/chrome/browser/tab_contents/tab_contents.cc
+++ b/chrome/browser/tab_contents/tab_contents.cc
@@ -37,6 +37,7 @@
 #include "chrome/browser/tab_contents/navigation_entry.h"
 #include "chrome/browser/tab_contents/tab_contents_delegate.h"
 #include "chrome/browser/tab_contents/tab_contents_view.h"
+#include "chrome/browser/thumbnail_store.h"
 #include "chrome/browser/search_engines/template_url_fetcher.h"
 #include "chrome/browser/search_engines/template_url_model.h"
 #include "chrome/common/chrome_switches.h"
@@ -1633,10 +1634,15 @@ void TabContents::UpdateThumbnail(const GURL& url,
                                   const SkBitmap& bitmap,
                                   const ThumbnailScore& score) {
   // Tell History about this thumbnail
-  HistoryService* hs;
-  if (!profile()->IsOffTheRecord() &&
-      (hs = profile()->GetHistoryService(Profile::IMPLICIT_ACCESS))) {
-    hs->SetPageThumbnail(url, bitmap, score);
+  if (CommandLine::ForCurrentProcess()->HasSwitch(switches::kThumbnailStore)) {
+    profile()->GetThumbnailStore()->
+        SetPageThumbnail(url, bitmap, score, !profile()->IsOffTheRecord());
+  } else {
+    HistoryService* hs;
+    if (!profile()->IsOffTheRecord() &&
+        (hs = profile()->GetHistoryService(Profile::IMPLICIT_ACCESS))) {
+      hs->SetPageThumbnail(url, bitmap, score);
+    }
   }
 }
 
diff --git a/chrome/browser/thumbnail_store.cc b/chrome/browser/thumbnail_store.cc
index 1745431..c599c20 100644
--- a/chrome/browser/thumbnail_store.cc
+++ b/chrome/browser/thumbnail_store.cc
@@ -23,62 +23,57 @@ ThumbnailStore::~ThumbnailStore() {
 }
 
 void ThumbnailStore::Init(const FilePath& file_path) {
-  file_path_ = file_path.DirName();
+  file_path_ = file_path;
   g_browser_process->file_thread()->message_loop()->PostTask(FROM_HERE,
       NewRunnableMethod(this, &ThumbnailStore::GetAllThumbnailsFromDisk,
                         file_path_, MessageLoop::current()));
 }
 
-void ThumbnailStore::OnDiskDataAvailable(ThumbnailStore::Cache* cache) {
-  if (cache) {
-    cache_.reset(cache);
-    cache_initialized_ = true;
-  }
-}
-
 void ThumbnailStore::GetAllThumbnailsFromDisk(FilePath filepath,
                                               MessageLoop* cb_loop) {
-  // Create the specified directory if it does not exist.
-  if (!file_util::DirectoryExists(filepath) &&
-      !file_util::CreateDirectory(filepath))
-    return;
-
-  // Walk the directory and read the thumbnail data from disk.
-  FilePath path;
-  GURL url;
-  SkBitmap image;
-  ThumbnailScore score;
   ThumbnailStore::Cache* cache = new ThumbnailStore::Cache;
-  file_util::FileEnumerator fenum(filepath, false,
-                                  file_util::FileEnumerator::FILES);
 
-  while (!(path = fenum.Next()).empty()) {
-    if (GetPageThumbnailFromDisk(path, &url, &image, &score))
-      (*cache)[url] = std::make_pair(image, score);
+  // Create the specified directory if it does not exist.
+  if (!file_util::DirectoryExists(filepath)) {
+    file_util::CreateDirectory(filepath);
+  } else {
+    // Walk the directory and read the thumbnail data from disk.
+    FilePath path;
+    GURL url;
+    RefCountedBytes* data = new RefCountedBytes;
+    ThumbnailScore score;
+    file_util::FileEnumerator fenum(filepath, false,
+                                    file_util::FileEnumerator::FILES);
+
+    while (!(path = fenum.Next()).empty()) {
+      if (GetPageThumbnailFromDisk(path, &url, data, &score))
+        (*cache)[url] = std::make_pair(data, score);
+    }
   }
-
   cb_loop->PostTask(FROM_HERE,
       NewRunnableMethod(this, &ThumbnailStore::OnDiskDataAvailable, cache));
 }
 
 bool ThumbnailStore::GetPageThumbnailFromDisk(const FilePath& file,
-                                              GURL* url, SkBitmap* thumbnail,
+                                              GURL* url,
+                                              RefCountedBytes* data,
                                               ThumbnailScore* score) const {
   int64 file_size;
   if (!file_util::GetFileSize(file, &file_size))
     return false;
 
   // Read the file into a buffer.
-  std::vector<char> data;
-  data.resize(static_cast<unsigned int>(file_size));
-  if (file_util::ReadFile(file, &data[0], static_cast<int>(file_size)) == -1)
+  std::vector<char> file_data;
+  file_data.resize(static_cast<unsigned int>(file_size));
+  if (file_util::ReadFile(file, &file_data[0],
+                          static_cast<int>(file_size)) == -1)
     return false;
 
   // Unpack the url, ThumbnailScore and JPEG size from the buffer.
   std::string url_string;
   unsigned int jpeg_len;
   void* iter = NULL;
-  Pickle packed(&data[0], static_cast<int>(file_size));
+  Pickle packed(&file_data[0], static_cast<int>(file_size));
 
   if (!packed.ReadString(&iter, &url_string) ||
       !UnpackScore(score, packed, iter) ||
@@ -90,25 +85,28 @@ bool ThumbnailStore::GetPageThumbnailFromDisk(const FilePath& file,
   url->Swap(&temp_url);
 
   // Unpack the JPEG data from the buffer.
-  if (thumbnail) {
-    const char* jpeg_data = NULL;
-    int out_len;
-
-    if (!packed.ReadData(&iter, &jpeg_data, &out_len) ||
-        out_len != jpeg_len)
-      return false;
-
-    // Convert the jpeg_data to an SkBitmap.
-    SkBitmap* thumbnail_ = JPEGCodec::Decode(
-        reinterpret_cast<const unsigned char*>(jpeg_data), jpeg_len);
-    *thumbnail = *thumbnail_;
-    delete thumbnail_;
-  }
+  const char* jpeg_data = NULL;
+  int out_len;
+
+  if (!packed.ReadData(&iter, &jpeg_data, &out_len) ||
+      out_len != jpeg_len)
+    return false;
+
+  // Copy jpeg data to the out parameter.
+  data->data.resize(jpeg_len);
+  memcpy(&data->data[0], jpeg_data, jpeg_len);
   return true;
 }
 
+void ThumbnailStore::OnDiskDataAvailable(ThumbnailStore::Cache* cache) {
+  if (cache) {
+    cache_.reset(cache);
+    cache_initialized_ = true;
+  }
+}
+
 bool ThumbnailStore::SetPageThumbnail(const GURL& url,
-                                      SkBitmap& thumbnail,
+                                      const SkBitmap& thumbnail,
                                       const ThumbnailScore& score,
                                       bool write_to_disk) {
   if (!cache_initialized_)
@@ -119,8 +117,26 @@ bool ThumbnailStore::SetPageThumbnail(const GURL& url,
       !ShouldReplaceThumbnailWith((*cache_)[url].second, score))
     return true;
 
+  base::TimeTicks encode_start = base::TimeTicks::Now();
+
+  // Encode the SkBitmap to jpeg and add to cache.
+  RefCountedBytes* jpeg_data = new RefCountedBytes;
+  SkAutoLockPixels thumbnail_lock(thumbnail);
+  bool encoded = JPEGCodec::Encode(
+      reinterpret_cast<unsigned char*>(thumbnail.getAddr32(0, 0)),
+      JPEGCodec::FORMAT_BGRA, thumbnail.width(),
+      thumbnail.height(),
+      static_cast<int>(thumbnail.rowBytes()), 90,
+      &jpeg_data->data);
+
+  base::TimeDelta delta = base::TimeTicks::Now() - encode_start;
+  HISTOGRAM_TIMES("Thumbnail.Encode", delta);
+
+  if (!encoded)
+    return false;
+
   // Update the cache_ with the new thumbnail.
-  (*cache_)[url] = std::make_pair(thumbnail, score);
+  (*cache_)[url] = std::make_pair(jpeg_data, score);
 
   // Write the new thumbnail data to disk in the background on file_thread.
   if (write_to_disk) {
@@ -134,27 +150,14 @@ bool ThumbnailStore::WriteThumbnailToDisk(const GURL& url) const {
   // Thumbnail data will be stored in a file named url.host().
   FilePath file = file_path_.AppendASCII(url.host());
   Pickle packed;
-  SkBitmap thumbnail = (*cache_)[url].first;
+  scoped_refptr<RefCountedBytes> data((*cache_)[url].first);
   ThumbnailScore score = (*cache_)[url].second;
 
-  // Convert the SkBitmap to a JPEG.
-  std::vector<unsigned char> jpeg_data;
-  SkAutoLockPixels thumbnail_lock(thumbnail);
-  bool encoded = JPEGCodec::Encode(
-      reinterpret_cast<unsigned char*>(thumbnail.getAddr32(0, 0)),
-      JPEGCodec::FORMAT_BGRA, thumbnail.width(),
-      thumbnail.height(),
-      static_cast<int>(thumbnail.rowBytes()), 90,
-      &jpeg_data);
-
-  if (!encoded)
-    return false;
-
   // Pack the url, ThumbnailScore, and the JPEG data.
   packed.WriteString(url.spec());
   PackScore(score, &packed);
-  packed.WriteUInt32(jpeg_data.size());
-  packed.WriteData(reinterpret_cast<char*>(&jpeg_data[0]), jpeg_data.size());
+  packed.WriteUInt32(data->data.size());
+  packed.WriteData(reinterpret_cast<char*>(&data->data[0]), data->data.size());
 
   // Write the packed data to a file.
   file_util::Delete(file, false);
@@ -163,14 +166,13 @@ bool ThumbnailStore::WriteThumbnailToDisk(const GURL& url) const {
                               packed.size()) != -1;
 }
 
-bool ThumbnailStore::GetPageThumbnail(const GURL& url, SkBitmap* thumbnail,
-                                      ThumbnailScore* score) {
+bool ThumbnailStore::GetPageThumbnail(const GURL& url, RefCountedBytes** data) {
   if (!cache_initialized_ ||
       cache_->find(url) == cache_->end())
     return false;
 
-  *thumbnail = (*cache_)[url].first;
-  *score = (*cache_)[url].second;
+  *data = (*cache_)[url].first;
+  (*data)->AddRef();
   return true;
 }
 
@@ -178,7 +180,7 @@ void ThumbnailStore::PackScore(const ThumbnailScore& score,
                                Pickle* packed) const {
   // Pack the contents of the given ThumbnailScore into the given Pickle.
   packed->WriteData(reinterpret_cast<const char*>(&score.boring_score),
-                   sizeof(score.boring_score));
+                    sizeof(score.boring_score));
   packed->WriteBool(score.at_top);
   packed->WriteBool(score.good_clipping);
   packed->WriteInt64(score.time_at_snapshot.ToInternalValue());
diff --git a/chrome/browser/thumbnail_store.h b/chrome/browser/thumbnail_store.h
index 46b6ae0..486f99c 100644
--- a/chrome/browser/thumbnail_store.h
+++ b/chrome/browser/thumbnail_store.h
@@ -11,6 +11,7 @@
 #include "base/file_path.h"
 #include "base/message_loop.h"
 #include "base/ref_counted.h"
+#include "chrome/common/ref_counted_util.h"
 #include "testing/gtest/include/gtest/gtest_prod.h"
 
 class GURL;
@@ -37,23 +38,22 @@ class ThumbnailStore : public base::RefCountedThreadSafe<ThumbnailStore> {
   // If write_to_disk is true, the thumbnail data is written to disk on the
   // file_thread.
   bool SetPageThumbnail(const GURL& url,
-                        SkBitmap& thumbnail,
+                        const SkBitmap& thumbnail,
                         const ThumbnailScore& score,
                         bool write_to_disk);
 
-  // Retrieves the thumbnail and score for the given url.
+  // Sets *data to point to the thumbnail for the given url.
   // Returns false if there is not data for the given url or some other
   // error occurred.
-  bool GetPageThumbnail(const GURL& url,
-                        SkBitmap* thumbnail,
-                        ThumbnailScore* score);
+  bool GetPageThumbnail(const GURL& url, RefCountedBytes** data);
 
  private:
   FRIEND_TEST(ThumbnailStoreTest, RetrieveFromCache);
   FRIEND_TEST(ThumbnailStoreTest, RetrieveFromDisk);
 
   // Data structure used to store thumbnail data in memory.
-  typedef std::map<GURL, std::pair<SkBitmap, ThumbnailScore> > Cache;
+  typedef std::map<GURL, std::pair<scoped_refptr<RefCountedBytes>,
+                                   ThumbnailScore> > Cache;
 
   // The location of the thumbnail store.
   FilePath file_path_;
@@ -67,7 +67,7 @@ class ThumbnailStore : public base::RefCountedThreadSafe<ThumbnailStore> {
   // out parameters GURL, SkBitmap, and ThumbnailScore.
   bool GetPageThumbnailFromDisk(const FilePath& file,
                                 GURL* url,
-                                SkBitmap* thumbnail,
+                                RefCountedBytes* data,
                                 ThumbnailScore* score) const;
 
   // Once thumbnail data from the disk is available from the file_thread,
@@ -86,11 +86,11 @@ class ThumbnailStore : public base::RefCountedThreadSafe<ThumbnailStore> {
   bool UnpackScore(ThumbnailScore* score, const Pickle& packed,
                    void*& iter) const;
 
-  DISALLOW_COPY_AND_ASSIGN(ThumbnailStore);
-
   // The Cache maintained by the object.
   scoped_ptr<ThumbnailStore::Cache> cache_;
   bool cache_initialized_;
+
+  DISALLOW_COPY_AND_ASSIGN(ThumbnailStore);
 };
 
 #endif  // CHROME_BROWSER_THUMBNAIL_STORE_H_
diff --git a/chrome/browser/thumbnail_store_unittest.cc b/chrome/browser/thumbnail_store_unittest.cc
index 53ec322..eb00993 100644
--- a/chrome/browser/thumbnail_store_unittest.cc
+++ b/chrome/browser/thumbnail_store_unittest.cc
@@ -12,7 +12,9 @@
 #include "base/file_util.h"
 #include "base/gfx/jpeg_codec.h"
 #include "base/path_service.h"
+#include "base/ref_counted.h"
 #include "chrome/common/chrome_paths.h"
+#include "chrome/common/ref_counted_util.h"
 #include "chrome/common/thumbnail_score.h"
 #include "chrome/tools/profiles/thumbnail-inl.h"
 #include "googleurl/src/gurl.h"
@@ -46,7 +48,8 @@ class ThumbnailStoreTest : public testing::Test {
   // The directory where ThumbnailStore will store data.
   FilePath file_path_;
 
-  SkBitmap read_image_, image_enc_dec_, image_;
+  SkBitmap image_;
+  scoped_refptr<RefCountedBytes> jpeg_image_;
   ThumbnailScore score1_, score2_;
   GURL url1_, url2_;
   base::Time time_;
@@ -63,21 +66,14 @@ void ThumbnailStoreTest::SetUp() {
   // image is the original SkBitmap representing the thumbnail
   image_ = *(JPEGCodec::Decode(kGoogleThumbnail, sizeof(kGoogleThumbnail)));
 
-  // The ThumbnailStore will encode the thumbnail to jpeg at 90% quality, so
-  // we do this to image.  When image is stored, image_enc_dec_ is what
-  // ThumbnailStore should return.
-  std::vector<unsigned char> jpeg_data;
   SkAutoLockPixels thumbnail_lock(image_);
+  jpeg_image_ = new RefCountedBytes;
   bool encoded = JPEGCodec::Encode(
       reinterpret_cast<unsigned char*>(image_.getAddr32(0, 0)),
       JPEGCodec::FORMAT_BGRA, image_.width(),
       image_.height(),
       static_cast<int>(image_.rowBytes()), 90,
-      &jpeg_data);
-
-  image_enc_dec_ = *(JPEGCodec::Decode(
-                        reinterpret_cast<const unsigned char*>(&jpeg_data[0]),
-                        jpeg_data.size()));
+      &(jpeg_image_->data));
 }
 
 void ThumbnailStoreTest::PrintPixelDiff(SkBitmap* image_a, SkBitmap* image_b) {
@@ -86,15 +82,20 @@ void ThumbnailStoreTest::PrintPixelDiff(SkBitmap* image_a, SkBitmap* image_b) {
   // differences should be small since encoding was done at 90% before
   // writing to disk.
 
+  if (image_a->height() != image_b->height() ||
+      image_b->width() != image_b->width() ||
+      image_a->rowBytes() != image_b->rowBytes())
+    return;
+
   SkAutoLockPixels lock_a(*image_a);
   SkAutoLockPixels lock_b(*image_b);
 
-  int ppr = read_image_.rowBytesAsPixels();
+  int ppr = image_a->rowBytesAsPixels();
   unsigned int *a, *b;
   unsigned int maxv[4];
   memset(maxv, 0, sizeof(maxv));
 
-  for (int nrows = read_image_.height()-1; nrows >= 0; nrows--) {
+  for (int nrows = image_a->height()-1; nrows >= 0; nrows--) {
     a = image_a->getAddr32(0, nrows);
     b = image_b->getAddr32(0, nrows);
     for (int i = 0; i < ppr; i += 4) {
@@ -114,61 +115,47 @@ void ThumbnailStoreTest::PrintPixelDiff(SkBitmap* image_a, SkBitmap* image_b) {
 }
 
 TEST_F(ThumbnailStoreTest, RetrieveFromCache) {
-  ThumbnailStore* store = new ThumbnailStore;
-  store->AddRef();
+  RefCountedBytes* read_image = NULL;
+  scoped_refptr<ThumbnailStore> store = new ThumbnailStore;
+
   store->file_path_ = file_path_;
   store->cache_.reset(new ThumbnailStore::Cache);
   store->cache_initialized_ = true;
 
-  read_image_.reset();
-
   // Retrieve a thumbnail/score for a nonexistent page.
 
-  EXPECT_FALSE(store->GetPageThumbnail(url2_, &read_image_, &score2_));
+  EXPECT_FALSE(store->GetPageThumbnail(url2_, &read_image));
 
   // Store a thumbnail into the cache and retrieve it.
 
   EXPECT_TRUE(store->SetPageThumbnail(url1_, image_, score1_, false));
-  EXPECT_TRUE(store->GetPageThumbnail(url1_, &read_image_, &score2_));
-  EXPECT_TRUE(score1_.Equals(score2_));
-  EXPECT_TRUE(read_image_.getSize() == image_.getSize());
-  EXPECT_TRUE(read_image_.pixelRef() == image_.pixelRef());
-  EXPECT_FALSE(read_image_.isNull());
+  EXPECT_TRUE(store->GetPageThumbnail(url1_, &read_image));
+  EXPECT_TRUE(score1_.Equals((*store->cache_)[url1_].second));
+  EXPECT_TRUE(read_image->data.size() == jpeg_image_->data.size());
+  EXPECT_EQ(0, memcmp(&read_image->data[0], &jpeg_image_->data[0],
+                      jpeg_image_->data.size()));
 
-  store->Release();
+  read_image->Release();
 }
 
 TEST_F(ThumbnailStoreTest, RetrieveFromDisk) {
-  ThumbnailStore* store = new ThumbnailStore;
-  store->AddRef();
+  scoped_refptr<RefCountedBytes> read_image = new RefCountedBytes;
+  scoped_refptr<ThumbnailStore> store = new ThumbnailStore;
+
   store->file_path_ = file_path_;
   store->cache_.reset(new ThumbnailStore::Cache);
   store->cache_initialized_ = true;
 
-  read_image_.reset();
-
   // Store a thumbnail onto the disk and retrieve it.
 
   EXPECT_TRUE(store->SetPageThumbnail(url1_, image_, score1_, false));
   EXPECT_TRUE(store->WriteThumbnailToDisk(url1_));
   EXPECT_TRUE(store->GetPageThumbnailFromDisk(
-      file_path_.AppendASCII(url1_.host()), &url2_, &read_image_, &score2_));
+      file_path_.AppendASCII(url1_.host()), &url2_, read_image, &score2_));
+  read_image->AddRef();
   EXPECT_TRUE(url1_ == url2_);
   EXPECT_TRUE(score1_.Equals(score2_));
-  EXPECT_TRUE(read_image_.getSize() == image_enc_dec_.getSize());
-  EXPECT_FALSE(read_image_.isNull());
-
-  // The retrieved SkBitmap should be the same as the original image
-  // encoded at 90% quality to jpeg, then decoded.
-
-  {
-    SkAutoLockPixels lock_a(read_image_);
-    SkAutoLockPixels lock_b(image_enc_dec_);
-    EXPECT_TRUE(0 == memcmp(read_image_.getPixels(),
-                            image_enc_dec_.getPixels(),
-                            read_image_.getSize()));
-  }
-  PrintPixelDiff(&read_image_, &image_);
-
-  store->Release();
+  EXPECT_TRUE(read_image->data.size() == jpeg_image_->data.size());
+  EXPECT_EQ(0, memcmp(&read_image->data[0], &jpeg_image_->data[0],
+                      jpeg_image_->data.size()));
 }
diff --git a/chrome/chrome.gyp b/chrome/chrome.gyp
index 219004d..3b65c85 100644
--- a/chrome/chrome.gyp
+++ b/chrome/chrome.gyp
@@ -1379,6 +1379,8 @@
         'browser/task_manager_resource_providers.h',
         'browser/theme_resources_util.cc',
         'browser/theme_resources_util.h',
+        'browser/thumbnail_store.cc',
+        'browser/thumbnail_store.h',
         'browser/toolbar_model.cc',
         'browser/toolbar_model.h',
         'browser/user_data_manager.cc',
@@ -3215,6 +3217,7 @@
         'browser/history/text_database_manager_unittest.cc',
         'browser/history/text_database_unittest.cc',
         'browser/history/thumbnail_database_unittest.cc',
+        'browser/thumbnail_store_unittest.cc',
         'browser/history/url_database_unittest.cc',
         'browser/history/visit_database_unittest.cc',
         'browser/history/visit_tracker_unittest.cc',
diff --git a/chrome/common/chrome_switches.cc b/chrome/common/chrome_switches.cc
index a9335ed..48511d3 100644
--- a/chrome/common/chrome_switches.cc
+++ b/chrome/common/chrome_switches.cc
@@ -490,4 +490,8 @@ const wchar_t kNoDefaultBrowserCheck[]         = L"no-default-browser-check";
 // Enables the benchmarking extensions.
 const wchar_t kEnableBenchmarking[]      = L"enable-benchmarking";
 
+// Enables using ThumbnailStore instead of ThumbnailDatabase for setting and
+// getting thumbnails for the new tab page.
+const wchar_t kThumbnailStore[]                = L"thumbnail-store";
+
 }  // namespace switches
diff --git a/chrome/common/chrome_switches.h b/chrome/common/chrome_switches.h
index 50666c8..8259d72 100644
--- a/chrome/common/chrome_switches.h
+++ b/chrome/common/chrome_switches.h
@@ -185,6 +185,8 @@ extern const wchar_t kEnableBenchmarking[];
 
 extern const wchar_t kNoDefaultBrowserCheck[];
 
+extern const wchar_t kThumbnailStore[];
+
 }  // namespace switches
 
 #endif  // CHROME_COMMON_CHROME_SWITCHES_H_
diff --git a/chrome/test/testing_profile.h b/chrome/test/testing_profile.h
index 40b88dd..56bfc38 100644
--- a/chrome/test/testing_profile.h
+++ b/chrome/test/testing_profile.h
@@ -121,6 +121,11 @@ class TestingProfile : public Profile {
   virtual TemplateURLFetcher* GetTemplateURLFetcher() {
     return NULL;
   }
+
+  virtual ThumbnailStore* GetThumbnailStore() {
+    return NULL;
+  }
+
   virtual DownloadManager* GetDownloadManager() {
     return NULL;
   }
diff --git a/chrome/test/unit/unittests.vcproj b/chrome/test/unit/unittests.vcproj
index 7c91621..f80b539 100644
--- a/chrome/test/unit/unittests.vcproj
+++ b/chrome/test/unit/unittests.vcproj
@@ -814,6 +814,10 @@
 				>
 			</File>
 			<File
+				RelativePath="..\..\browser\thumbnail_store_unittest.cc"
+				>
+			</File>
+			<File
 				RelativePath="..\..\browser\history\url_database_unittest.cc"
 				>
 			</File>