Disk cache: Update the disk cache tools and tests to use

the new interface (provide a cache thread and callback).

BUG=26730
TEST=unit tests


Review URL: http://codereview.chromium.org/2739007

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@49819 0039d316-1c4b-4281-b951-d872f2087c98

11 files changed, 221 insertions, 106 deletions

diff --git a/net/disk_cache/backend_impl.cc b/net/disk_cache/backend_impl.cc
index edd5c59..8fa56f0 100644
--- a/net/disk_cache/backend_impl.cc
+++ b/net/disk_cache/backend_impl.cc
@@ -1,4 +1,4 @@
-// Copyright (c) 2010 The Chromium Authors. All rights reserved.
+// Copyright (c) 2006-2010 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.
 
@@ -20,6 +20,7 @@
 #include "net/disk_cache/errors.h"
 #include "net/disk_cache/hash.h"
 #include "net/disk_cache/file.h"
+#include "net/disk_cache/mem_backend_impl.h"
 
 // This has to be defined before including histogram_macros.h from this file.
 #define NET_DISK_CACHE_BACKEND_IMPL_CC_
@@ -167,20 +168,18 @@ void SetFieldTrialInfo(int size_group) {
 
 namespace disk_cache {
 
-Backend* CreateCacheBackend(const FilePath& full_path, bool force,
-                            int max_bytes, net::CacheType type) {
-  // Create a backend without extra flags.
-  return BackendImpl::CreateBackend(full_path, force, max_bytes, type, kNone);
-}
-
 int CreateCacheBackend(net::CacheType type, const FilePath& path, int max_bytes,
                        bool force, base::MessageLoopProxy* thread,
                        Backend** backend, CompletionCallback* callback) {
-  if (type == net::MEMORY_CACHE)
-    *backend = CreateInMemoryCacheBackend(max_bytes);
-  else
-    *backend = BackendImpl::CreateBackend(path, force, max_bytes, type, kNone);
-  return *backend ? net::OK : net::ERR_FAILED;
+  DCHECK(callback);
+  if (type == net::MEMORY_CACHE) {
+    *backend = MemBackendImpl::CreateBackend(max_bytes);
+    return *backend ? net::OK : net::ERR_FAILED;
+  }
+  DCHECK(thread);
+
+  return BackendImpl::CreateBackend(path, force, max_bytes, type, kNone, thread,
+                                    backend, callback);
 }
 
 // Returns the preferred maximum number of bytes for the cache given the
@@ -224,35 +223,42 @@ int PreferedCacheSize(int64 available) {
 // desired path) cannot be created.
 //
 // Static.
-Backend* BackendImpl::CreateBackend(const FilePath& full_path, bool force,
-                                    int max_bytes, net::CacheType type,
-                                    BackendFlags flags) {
-  BackendImpl* cache = new BackendImpl(full_path);
+int BackendImpl::CreateBackend(const FilePath& full_path, bool force,
+                               int max_bytes, net::CacheType type,
+                               uint32 flags, base::MessageLoopProxy* thread,
+                               Backend** backend,
+                               CompletionCallback* callback) {
+  BackendImpl* cache = new BackendImpl(full_path, thread);
   cache->SetMaxSize(max_bytes);
   cache->SetType(type);
   cache->SetFlags(flags);
-  if (cache->Init())
-    return cache;
+  if (cache->Init()) {
+    *backend = cache;
+    return net::OK;
+  }
 
+  *backend = NULL;
   delete cache;
   if (!force)
-    return NULL;
+    return net::ERR_FAILED;
 
   if (!DelayedCacheCleanup(full_path))
-    return NULL;
+    return net::ERR_FAILED;
 
   // The worker thread will start deleting files soon, but the original folder
   // is not there anymore... let's create a new set of files.
-  cache = new BackendImpl(full_path);
+  cache = new BackendImpl(full_path, thread);
   cache->SetMaxSize(max_bytes);
   cache->SetType(type);
   cache->SetFlags(flags);
-  if (cache->Init())
-    return cache;
+  if (cache->Init()) {
+    *backend = cache;
+    return net::OK;
+  }
 
   delete cache;
   LOG(ERROR) << "Unable to create cache";
-  return NULL;
+  return net::ERR_FAILED;
 }
 
 bool BackendImpl::Init() {
diff --git a/net/disk_cache/backend_impl.h b/net/disk_cache/backend_impl.h
index 58d81eb..aa87a63 100644
--- a/net/disk_cache/backend_impl.h
+++ b/net/disk_cache/backend_impl.h
@@ -1,4 +1,4 @@
-// Copyright (c) 2010 The Chromium Authors. All rights reserved.
+// Copyright (c) 2006-2010 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.
 
@@ -35,14 +35,15 @@ enum BackendFlags {
 class BackendImpl : public Backend {
   friend class Eviction;
  public:
-  explicit BackendImpl(const FilePath& path)
+  BackendImpl(const FilePath& path, base::MessageLoopProxy* cache_thread)
       : path_(path), block_files_(path), mask_(0), max_size_(0),
         cache_type_(net::DISK_CACHE), uma_report_(0), user_flags_(0),
         init_(false), restarted_(false), unit_test_(false), read_only_(false),
         new_eviction_(false), first_timer_(true),
         ALLOW_THIS_IN_INITIALIZER_LIST(factory_(this)) {}
   // mask can be used to limit the usable size of the hash table, for testing.
-  BackendImpl(const FilePath& path, uint32 mask)
+  BackendImpl(const FilePath& path, uint32 mask,
+              base::MessageLoopProxy* cache_thread)
       : path_(path), block_files_(path), mask_(mask), max_size_(0),
         cache_type_(net::DISK_CACHE), uma_report_(0), user_flags_(kMask),
         init_(false), restarted_(false), unit_test_(false), read_only_(false),
@@ -52,9 +53,10 @@ class BackendImpl : public Backend {
 
   // Returns a new backend with the desired flags. See the declaration of
   // CreateCacheBackend().
-  static Backend* CreateBackend(const FilePath& full_path, bool force,
-                                int max_bytes, net::CacheType type,
-                                BackendFlags flags);
+  static int CreateBackend(const FilePath& full_path, bool force,
+                           int max_bytes, net::CacheType type,
+                           uint32 flags, base::MessageLoopProxy* thread,
+                           Backend** backend, CompletionCallback* callback);
 
   // Performs general initialization for this current instance of the cache.
   bool Init();
diff --git a/net/disk_cache/backend_unittest.cc b/net/disk_cache/backend_unittest.cc
index 41c8069..c659088 100644
--- a/net/disk_cache/backend_unittest.cc
+++ b/net/disk_cache/backend_unittest.cc
@@ -7,6 +7,7 @@
 #include "base/path_service.h"
 #include "base/platform_thread.h"
 #include "base/string_util.h"
+#include "base/thread.h"
 #include "net/base/io_buffer.h"
 #include "net/base/net_errors.h"
 #include "net/base/test_completion_callback.h"
@@ -15,6 +16,7 @@
 #include "net/disk_cache/disk_cache_test_util.h"
 #include "net/disk_cache/histogram_macros.h"
 #include "net/disk_cache/mapped_file.h"
+#include "net/disk_cache/mem_backend_impl.h"
 #include "testing/gtest/include/gtest/gtest.h"
 
 using base::Time;
@@ -187,6 +189,49 @@ TEST_F(DiskCacheBackendTest, MemoryOnlyKeying) {
   BackendKeying();
 }
 
+TEST_F(DiskCacheTest, CreateBackend) {
+  TestCompletionCallback cb;
+
+  {
+    FilePath path = GetCacheFilePath();
+    ASSERT_TRUE(DeleteCache(path));
+    base::Thread cache_thread("CacheThread");
+    ASSERT_TRUE(cache_thread.StartWithOptions(
+                    base::Thread::Options(MessageLoop::TYPE_IO, 0)));
+
+    // Test the private factory methods.
+    disk_cache::Backend* cache = NULL;
+    int rv = disk_cache::BackendImpl::CreateBackend(
+                 path, false, 0, net::DISK_CACHE, disk_cache::kNoRandom,
+                 cache_thread.message_loop_proxy(), &cache, &cb);
+    ASSERT_EQ(net::OK, cb.GetResult(rv));
+    ASSERT_TRUE(cache);
+    delete cache;
+
+    cache = disk_cache::MemBackendImpl::CreateBackend(0);
+    ASSERT_TRUE(cache);
+    delete cache;
+    cache = NULL;
+
+    // Now test the public API.
+    rv = disk_cache::CreateCacheBackend(net::DISK_CACHE, path, 0, false,
+                                        cache_thread.message_loop_proxy(),
+                                        &cache, &cb);
+    ASSERT_EQ(net::OK, cb.GetResult(rv));
+    ASSERT_TRUE(cache);
+    delete cache;
+    cache = NULL;
+
+    rv = disk_cache::CreateCacheBackend(net::MEMORY_CACHE, FilePath(), 0, false,
+                                        NULL, &cache, &cb);
+    ASSERT_EQ(net::OK, cb.GetResult(rv));
+    ASSERT_TRUE(cache);
+    delete cache;
+  }
+
+  MessageLoop::current()->RunAllPending();
+}
+
 TEST_F(DiskCacheBackendTest, ExternalFiles) {
   InitCache();
   // First, lets create a file on the folder.
@@ -215,12 +260,19 @@ TEST_F(DiskCacheTest, ShutdownWithPendingIO) {
   {
     FilePath path = GetCacheFilePath();
     ASSERT_TRUE(DeleteCache(path));
+    base::Thread cache_thread("CacheThread");
+    ASSERT_TRUE(cache_thread.StartWithOptions(
+                    base::Thread::Options(MessageLoop::TYPE_IO, 0)));
 
-    disk_cache::Backend* cache =
-        disk_cache::CreateCacheBackend(path, false, 0, net::DISK_CACHE);
+    disk_cache::Backend* cache;
+    int rv = disk_cache::BackendImpl::CreateBackend(
+                 path, false, 0, net::DISK_CACHE, disk_cache::kNoRandom,
+                 cache_thread.message_loop_proxy(), &cache, &callback);
+    ASSERT_EQ(net::OK, callback.GetResult(rv));
 
     disk_cache::Entry* entry;
-    ASSERT_TRUE(cache->CreateEntry("some key", &entry));
+    rv = cache->CreateEntry("some key", &entry, &callback);
+    ASSERT_EQ(net::OK, callback.GetResult(rv));
 
     const int kSize = 25000;
     scoped_refptr<net::IOBuffer> buffer = new net::IOBuffer(kSize);
@@ -247,11 +299,20 @@ TEST_F(DiskCacheTest, TruncatedIndex) {
   ASSERT_TRUE(DeleteCache(path));
   FilePath index = path.AppendASCII("index");
   ASSERT_EQ(5, file_util::WriteFile(index, "hello", 5));
-  scoped_ptr<disk_cache::Backend> backend;
-  backend.reset(disk_cache::BackendImpl::CreateBackend(path, false, 0,
-                                                       net::DISK_CACHE,
-                                                       disk_cache::kNone));
-  ASSERT_TRUE(backend.get() == NULL);
+
+  base::Thread cache_thread("CacheThread");
+  ASSERT_TRUE(cache_thread.StartWithOptions(
+                  base::Thread::Options(MessageLoop::TYPE_IO, 0)));
+  TestCompletionCallback cb;
+
+  disk_cache::Backend* backend = NULL;
+  int rv = disk_cache::BackendImpl::CreateBackend(
+               path, false, 0, net::DISK_CACHE, disk_cache::kNone,
+               cache_thread.message_loop_proxy(), &backend, &cb);
+  ASSERT_NE(net::OK, cb.GetResult(rv));
+
+  ASSERT_TRUE(backend == NULL);
+  delete backend;
 }
 
 void DiskCacheBackendTest::BackendSetSize() {
@@ -1088,20 +1149,26 @@ TEST_F(DiskCacheBackendTest, NewEvictionRecoverRemove) {
 }
 
 // Tests dealing with cache files that cannot be recovered.
-TEST_F(DiskCacheTest, Backend_DeleteOld) {
+TEST_F(DiskCacheTest, DeleteOld) {
   ASSERT_TRUE(CopyTestCache(L"wrong_version"));
   FilePath path = GetCacheFilePath();
-  scoped_ptr<disk_cache::Backend> cache;
-  cache.reset(disk_cache::CreateCacheBackend(path, true, 0, net::DISK_CACHE));
+  base::Thread cache_thread("CacheThread");
+  ASSERT_TRUE(cache_thread.StartWithOptions(
+                  base::Thread::Options(MessageLoop::TYPE_IO, 0)));
+  TestCompletionCallback cb;
+
+  disk_cache::Backend* cache;
+  int rv = disk_cache::BackendImpl::CreateBackend(
+               path, true, 0, net::DISK_CACHE, disk_cache::kNoRandom,
+               cache_thread.message_loop_proxy(), &cache, &cb);
+  ASSERT_EQ(net::OK, cb.GetResult(rv));
 
   MessageLoopHelper helper;
 
-  ASSERT_TRUE(NULL != cache.get());
+  ASSERT_TRUE(NULL != cache);
   ASSERT_EQ(0, cache->GetEntryCount());
 
-  // Wait for a callback that never comes... about 2 secs :). The message loop
-  // has to run to allow destruction of the cleaner thread.
-  helper.WaitUntilCacheIoFinished(1);
+  delete cache;
 }
 
 // We want to be able to deal with messed up entries on disk.
@@ -1443,7 +1510,8 @@ TEST_F(DiskCacheTest, Backend_UsageStats) {
   FilePath path = GetCacheFilePath();
   ASSERT_TRUE(DeleteCache(path));
   scoped_ptr<disk_cache::BackendImpl> cache;
-  cache.reset(new disk_cache::BackendImpl(path));
+  cache.reset(new disk_cache::BackendImpl(
+                  path, base::MessageLoopProxy::CreateForCurrentThread()));
   ASSERT_TRUE(NULL != cache.get());
   cache->SetUnitTestMode();
   ASSERT_TRUE(cache->Init());
@@ -1546,23 +1614,34 @@ TEST_F(DiskCacheTest, MultipleInstances) {
   ScopedTestCache store1;
   ScopedTestCache store2("cache_test2");
   ScopedTestCache store3("cache_test3");
+  base::Thread cache_thread("CacheThread");
+  ASSERT_TRUE(cache_thread.StartWithOptions(
+                  base::Thread::Options(MessageLoop::TYPE_IO, 0)));
+  TestCompletionCallback cb;
 
   const int kNumberOfCaches = 2;
-  scoped_ptr<disk_cache::Backend> cache[kNumberOfCaches];
+  disk_cache::Backend* cache[kNumberOfCaches];
 
-  cache[0].reset(disk_cache::CreateCacheBackend(store1.path(), false, 0,
-                                                net::DISK_CACHE));
-  cache[1].reset(disk_cache::CreateCacheBackend(store2.path(), false, 0,
-                                                net::MEDIA_CACHE));
+  int rv = disk_cache::BackendImpl::CreateBackend(
+               store1.path(), false, 0, net::DISK_CACHE, disk_cache::kNone,
+               cache_thread.message_loop_proxy(), &cache[0], &cb);
+  ASSERT_EQ(net::OK, cb.GetResult(rv));
+  rv = disk_cache::BackendImpl::CreateBackend(
+           store2.path(), false, 0, net::MEDIA_CACHE, disk_cache::kNone,
+           cache_thread.message_loop_proxy(), &cache[1], &cb);
+  ASSERT_EQ(net::OK, cb.GetResult(rv));
 
-  ASSERT_TRUE(cache[0].get() != NULL && cache[1].get() != NULL);
+  ASSERT_TRUE(cache[0] != NULL && cache[1] != NULL);
 
   std::string key("the first key");
   disk_cache::Entry* entry;
   for (int i = 0; i < kNumberOfCaches; i++) {
-    ASSERT_TRUE(cache[i]->CreateEntry(key, &entry));
+    rv = cache[i]->CreateEntry(key, &entry, &cb);
+    ASSERT_EQ(net::OK, cb.GetResult(rv));
     entry->Close();
   }
+  delete cache[0];
+  delete cache[1];
 }
 
 // Test the six regions of the curve that determines the max cache size.
diff --git a/net/disk_cache/disk_cache.h b/net/disk_cache/disk_cache.h
index 36151ad..2cddf6f 100644
--- a/net/disk_cache/disk_cache.h
+++ b/net/disk_cache/disk_cache.h
@@ -32,27 +32,6 @@ class Entry;
 class Backend;
 typedef net::CompletionCallback CompletionCallback;
 
-// Returns an instance of the Backend. path points to a folder where
-// the cached data will be stored. This cache instance must be the only object
-// that will be reading or writing files to that folder. The returned object
-// should be deleted when not needed anymore. If force is true, and there is
-// a problem with the cache initialization, the files will be deleted and a
-// new set will be created. max_bytes is the maximum size the cache can grow to.
-// If zero is passed in as max_bytes, the cache will determine the value to use
-// based on the available disk space. The returned pointer can be NULL if a
-// fatal error is found.
-// Note: This function is deprecated.
-Backend* CreateCacheBackend(const FilePath& path, bool force,
-                            int max_bytes, net::CacheType type);
-
-// Returns an instance of a Backend implemented only in memory. The returned
-// object should be deleted when not needed anymore. max_bytes is the maximum
-// size the cache can grow to. If zero is passed in as max_bytes, the cache will
-// determine the value to use based on the available memory. The returned
-// pointer can be NULL if a fatal error is found.
-// Note: This function is deprecated.
-Backend* CreateInMemoryCacheBackend(int max_bytes);
-
 // Returns an instance of a Backend of the given |type|. |path| points to a
 // folder where the cached data will be stored (if appropriate). This cache
 // instance must be the only object that will be reading or writing files to
diff --git a/net/disk_cache/disk_cache_perftest.cc b/net/disk_cache/disk_cache_perftest.cc
index 4064341..6e0ca8a 100644
--- a/net/disk_cache/disk_cache_perftest.cc
+++ b/net/disk_cache/disk_cache_perftest.cc
@@ -1,4 +1,4 @@
-// Copyright (c) 2006-2008 The Chromium Authors. All rights reserved.
+// Copyright (c) 2006-2010 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.
 
@@ -9,10 +9,12 @@
 #include "base/file_util.h"
 #include "base/perftimer.h"
 #include "base/string_util.h"
+#include "base/thread.h"
 #include "base/test/test_file_util.h"
 #include "base/timer.h"
 #include "net/base/io_buffer.h"
 #include "net/base/net_errors.h"
+#include "net/base/test_completion_callback.h"
 #include "net/disk_cache/block_files.h"
 #include "net/disk_cache/disk_cache.h"
 #include "net/disk_cache/disk_cache_test_util.h"
@@ -154,11 +156,18 @@ TEST_F(DiskCacheTest, Hash) {
 TEST_F(DiskCacheTest, CacheBackendPerformance) {
   MessageLoopForIO message_loop;
 
+  base::Thread cache_thread("CacheThread");
+  ASSERT_TRUE(cache_thread.StartWithOptions(
+                  base::Thread::Options(MessageLoop::TYPE_IO, 0)));
+
   ScopedTestCache test_cache;
-  disk_cache::Backend* cache =
-      disk_cache::CreateCacheBackend(test_cache.path(), false, 0,
-                                     net::DISK_CACHE);
-  ASSERT_TRUE(NULL != cache);
+  TestCompletionCallback cb;
+  disk_cache::Backend* cache;
+  int rv = disk_cache::CreateCacheBackend(
+               net::DISK_CACHE, test_cache.path(), 0, false,
+               cache_thread.message_loop_proxy(), &cache, &cb);
+
+  ASSERT_EQ(net::OK, cb.GetResult(rv));
 
   int seed = static_cast<int>(Time::Now().ToInternalValue());
   srand(seed);
@@ -183,9 +192,10 @@ TEST_F(DiskCacheTest, CacheBackendPerformance) {
   ASSERT_TRUE(file_util::EvictFileFromSystemCache(
               test_cache.path().AppendASCII("data_3")));
 
-  cache = disk_cache::CreateCacheBackend(test_cache.path(), false, 0,
-                                         net::DISK_CACHE);
-  ASSERT_TRUE(NULL != cache);
+  rv = disk_cache::CreateCacheBackend(net::DISK_CACHE, test_cache.path(), 0,
+                                      false, cache_thread.message_loop_proxy(),
+                                      &cache, &cb);
+  ASSERT_EQ(net::OK, cb.GetResult(rv));
 
   ret = TimeRead(num_entries, cache, entries, true);
   EXPECT_EQ(ret, g_cache_tests_received);
diff --git a/net/disk_cache/disk_cache_test_base.cc b/net/disk_cache/disk_cache_test_base.cc
index 2738674..7b0cc8e 100644
--- a/net/disk_cache/disk_cache_test_base.cc
+++ b/net/disk_cache/disk_cache_test_base.cc
@@ -38,7 +38,7 @@ void DiskCacheTestWithCache::InitCache() {
 
 void DiskCacheTestWithCache::InitMemoryCache() {
   if (!implementation_) {
-    cache_ = disk_cache::CreateInMemoryCacheBackend(size_);
+    cache_ = disk_cache::MemBackendImpl::CreateBackend(size_);
     return;
   }
 
@@ -57,19 +57,30 @@ void DiskCacheTestWithCache::InitDiskCache() {
   if (first_cleanup_)
     ASSERT_TRUE(DeleteCache(path));
 
+  if (!cache_thread_.IsRunning()) {
+    EXPECT_TRUE(cache_thread_.StartWithOptions(
+                    base::Thread::Options(MessageLoop::TYPE_IO, 0)));
+  }
+  ASSERT_TRUE(cache_thread_.message_loop() != NULL);
+
   if (implementation_)
     return InitDiskCacheImpl(path);
 
-  cache_ = disk_cache::BackendImpl::CreateBackend(path, force_creation_, size_,
-                                                  net::DISK_CACHE,
-                                                  disk_cache::kNoRandom);
+  TestCompletionCallback cb;
+  int rv = disk_cache::BackendImpl::CreateBackend(
+               path, force_creation_, size_, net::DISK_CACHE,
+               disk_cache::kNoRandom, cache_thread_.message_loop_proxy(),
+               &cache_, &cb);
+  ASSERT_EQ(net::OK, cb.GetResult(rv));
 }
 
 void DiskCacheTestWithCache::InitDiskCacheImpl(const FilePath& path) {
   if (mask_)
-    cache_impl_ = new disk_cache::BackendImpl(path, mask_);
+    cache_impl_ = new disk_cache::BackendImpl(
+                      path, mask_, cache_thread_.message_loop_proxy());
   else
-    cache_impl_ = new disk_cache::BackendImpl(path);
+    cache_impl_ = new disk_cache::BackendImpl(
+                      path, cache_thread_.message_loop_proxy());
 
   cache_ = cache_impl_;
   ASSERT_TRUE(NULL != cache_);
@@ -87,6 +98,8 @@ void DiskCacheTestWithCache::InitDiskCacheImpl(const FilePath& path) {
 void DiskCacheTestWithCache::TearDown() {
   MessageLoop::current()->RunAllPending();
   delete cache_;
+  if (cache_thread_.IsRunning())
+    cache_thread_.Stop();
 
   if (!memory_only_ && integrity_) {
     FilePath path = GetCacheFilePath();
diff --git a/net/disk_cache/disk_cache_test_base.h b/net/disk_cache/disk_cache_test_base.h
index 0878a38..f3c8040 100644
--- a/net/disk_cache/disk_cache_test_base.h
+++ b/net/disk_cache/disk_cache_test_base.h
@@ -6,7 +6,7 @@
 #define NET_DISK_CACHE_DISK_CACHE_TEST_BASE_H_
 
 #include "base/basictypes.h"
-#include "base/time.h"
+#include "base/thread.h"
 #include "testing/gtest/include/gtest/gtest.h"
 #include "testing/platform_test.h"
 
@@ -35,7 +35,8 @@ class DiskCacheTestWithCache : public DiskCacheTest {
   DiskCacheTestWithCache()
       : cache_(NULL), cache_impl_(NULL), mem_cache_(NULL), mask_(0), size_(0),
         memory_only_(false), implementation_(false), force_creation_(false),
-        new_eviction_(false), first_cleanup_(true), integrity_(true) {}
+        new_eviction_(false), first_cleanup_(true), integrity_(true),
+        cache_thread_("CacheThread") {}
 
   void InitCache();
   virtual void TearDown();
@@ -105,6 +106,9 @@ class DiskCacheTestWithCache : public DiskCacheTest {
   void InitMemoryCache();
   void InitDiskCache();
   void InitDiskCacheImpl(const FilePath& path);
+
+  base::Thread cache_thread_;
+  DISALLOW_COPY_AND_ASSIGN(DiskCacheTestWithCache);
 };
 
 #endif  // NET_DISK_CACHE_DISK_CACHE_TEST_BASE_H_
diff --git a/net/disk_cache/disk_cache_test_util.cc b/net/disk_cache/disk_cache_test_util.cc
index 36d28d2..480ba1d 100644
--- a/net/disk_cache/disk_cache_test_util.cc
+++ b/net/disk_cache/disk_cache_test_util.cc
@@ -1,4 +1,4 @@
-// Copyright (c) 2006-2009 The Chromium Authors. All rights reserved.
+// Copyright (c) 2006-2010 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.
 
@@ -6,6 +6,7 @@
 
 #include "base/logging.h"
 #include "base/file_util.h"
+#include "base/message_loop_proxy.h"
 #include "base/path_service.h"
 #include "net/disk_cache/backend_impl.h"
 #include "net/disk_cache/cache_util.h"
@@ -77,7 +78,8 @@ bool DeleteCache(const FilePath& path) {
 }
 
 bool CheckCacheIntegrity(const FilePath& path, bool new_eviction) {
-  scoped_ptr<disk_cache::BackendImpl> cache(new disk_cache::BackendImpl(path));
+  scoped_ptr<disk_cache::BackendImpl> cache(new disk_cache::BackendImpl(
+      path, base::MessageLoopProxy::CreateForCurrentThread()));
   if (!cache.get())
     return false;
   if (new_eviction)
diff --git a/net/disk_cache/mem_backend_impl.cc b/net/disk_cache/mem_backend_impl.cc
index 875efdc..fe57d7d 100644
--- a/net/disk_cache/mem_backend_impl.cc
+++ b/net/disk_cache/mem_backend_impl.cc
@@ -1,4 +1,4 @@
-// Copyright (c) 2006-2009 The Chromium Authors. All rights reserved.
+// Copyright (c) 2006-2010 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.
 
@@ -28,7 +28,8 @@ int LowWaterAdjust(int high_water) {
 
 namespace disk_cache {
 
-Backend* CreateInMemoryCacheBackend(int max_bytes) {
+// Static.
+Backend* MemBackendImpl::CreateBackend(int max_bytes) {
   MemBackendImpl* cache = new MemBackendImpl();
   cache->SetMaxSize(max_bytes);
   if (cache->Init())
@@ -39,8 +40,6 @@ Backend* CreateInMemoryCacheBackend(int max_bytes) {
   return NULL;
 }
 
-// ------------------------------------------------------------------------
-
 bool MemBackendImpl::Init() {
   if (max_size_)
     return true;
diff --git a/net/disk_cache/mem_backend_impl.h b/net/disk_cache/mem_backend_impl.h
index e687410..2072a56 100644
--- a/net/disk_cache/mem_backend_impl.h
+++ b/net/disk_cache/mem_backend_impl.h
@@ -23,6 +23,13 @@ class MemBackendImpl : public Backend {
   MemBackendImpl() : max_size_(0), current_size_(0) {}
   ~MemBackendImpl();
 
+  // Returns an instance of a Backend implemented only in memory. The returned
+  // object should be deleted when not needed anymore. max_bytes is the maximum
+  // size the cache can grow to. If zero is passed in as max_bytes, the cache
+  // will determine the value to use based on the available memory. The returned
+  // pointer can be NULL if a fatal error is found.
+  static Backend* CreateBackend(int max_bytes);
+
   // Performs general initialization for this current instance of the cache.
   bool Init();
 
diff --git a/net/disk_cache/stress_cache.cc b/net/disk_cache/stress_cache.cc
index 3619a5f..f5c7880 100644
--- a/net/disk_cache/stress_cache.cc
+++ b/net/disk_cache/stress_cache.cc
@@ -1,4 +1,4 @@
-// Copyright (c) 2006-2008 The Chromium Authors. All rights reserved.
+// Copyright (c) 2006-2010 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.
 
@@ -24,6 +24,8 @@
 #include "base/process_util.h"
 #include "base/string_util.h"
 #include "base/thread.h"
+#include "net/base/net_errors.h"
+#include "net/base/test_completion_callback.h"
 #include "net/base/io_buffer.h"
 #include "net/disk_cache/backend_impl.h"
 #include "net/disk_cache/disk_cache.h"
@@ -77,11 +79,20 @@ int MasterCode() {
 void StressTheCache(int iteration) {
   int cache_size = 0x800000;  // 8MB
   FilePath path = GetCacheFilePath().AppendASCII("_stress");
-  disk_cache::BackendImpl* cache = new disk_cache::BackendImpl(path);
-  cache->SetFlags(disk_cache::kNoLoadProtection | disk_cache::kNoRandom);
-  cache->SetMaxSize(cache_size);
-  cache->SetType(net::DISK_CACHE);
-  if (!cache->Init()) {
+
+  base::Thread cache_thread("CacheThread");
+  if (!cache_thread.StartWithOptions(
+          base::Thread::Options(MessageLoop::TYPE_IO, 0)))
+    return;
+
+  TestCompletionCallback cb;
+  disk_cache::Backend* cache;
+  int rv = disk_cache::BackendImpl::CreateBackend(
+               path, false, cache_size, net::DISK_CACHE,
+               disk_cache::kNoLoadProtection | disk_cache::kNoRandom,
+               cache_thread.message_loop_proxy(), &cache, &cb);
+
+  if (cb.GetResult(rv) != net::OK) {
     printf("Unable to initialize cache.\n");
     return;
   }
@@ -111,12 +122,15 @@ void StressTheCache(int iteration) {
     if (entries[slot])
       entries[slot]->Close();
 
-    if (!cache->OpenEntry(keys[key], &entries[slot]))
-      CHECK(cache->CreateEntry(keys[key], &entries[slot]));
+    rv = cache->OpenEntry(keys[key], &entries[slot], &cb);
+    if (cb.GetResult(rv) != net::OK) {
+      rv = cache->CreateEntry(keys[key], &entries[slot], &cb);
+      CHECK_EQ(net::OK, cb.GetResult(rv));
+    }
 
     base::snprintf(buffer->data(), kSize, "%d %d", iteration, i);
-    CHECK_EQ(kSize,
-             entries[slot]->WriteData(0, 0, buffer, kSize, NULL, false));
+    rv = entries[slot]->WriteData(0, 0, buffer, kSize, &cb, false);
+    CHECK_EQ(kSize, cb.GetResult(rv));
 
     if (rand() % 100 > 80) {
       key = rand() % kNumKeys;