Revert 223913 "Use SNAPSHOT sync mode for LocalSync"

This apparently was racy, see http://crbug.com/294499

> Use SNAPSHOT sync mode for LocalSync
> 
> LocalFileSyncService keeps the returned snapshot around until
> ApplyLocalChange finishes, so this change must be transparent
> to the remote side.
> 
> This patch depends on: https://codereview.chromium.org/24106002/
> 
> BUG=175693
> TEST=LocalFileSyncContextTest.PrepareSync_WriteDuringSync_*
> TEST=DriveFileSyncServiceSyncTest.*
> TEST=manual
> 
> Review URL: https://chromiumcodereview.appspot.com/23578026

TBR=kinuko@chromium.org

Review URL: https://codereview.chromium.org/23452045

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@224019 0039d316-1c4b-4281-b951-d872f2087c98

14 files changed, 84 insertions, 270 deletions

diff --git a/chrome/browser/sync_file_system/drive_backend_v1/drive_file_sync_service.cc b/chrome/browser/sync_file_system/drive_backend_v1/drive_file_sync_service.cc
index 39f2db2..e2a93d5 100644
--- a/chrome/browser/sync_file_system/drive_backend_v1/drive_file_sync_service.cc
+++ b/chrome/browser/sync_file_system/drive_backend_v1/drive_file_sync_service.cc
@@ -48,6 +48,15 @@ typedef RemoteFileSyncService::OriginStatusMap OriginStatusMap;
 namespace {
 
 const base::FilePath::CharType kTempDirName[] = FILE_PATH_LITERAL("tmp");
+const base::FilePath::CharType kSyncFileSystemDir[] =
+    FILE_PATH_LITERAL("Sync FileSystem");
+const base::FilePath::CharType kSyncFileSystemDirDev[] =
+    FILE_PATH_LITERAL("Sync FileSystem Dev");
+
+const base::FilePath::CharType* GetSyncFileSystemDir() {
+  return IsSyncFSDirectoryOperationEnabled()
+      ? kSyncFileSystemDirDev : kSyncFileSystemDir;
+}
 
 void EmptyStatusCallback(SyncStatusCode status) {}
 
@@ -342,14 +351,14 @@ void DriveFileSyncService::Initialize(
 
   task_manager_ = task_manager.Pass();
 
-  temporary_file_dir_ = sync_file_system::GetSyncFileSystemDir(
-      profile_->GetPath()).Append(kTempDirName);
+  temporary_file_dir_ =
+      profile_->GetPath().Append(GetSyncFileSystemDir()).Append(kTempDirName);
 
   api_util_.reset(new drive_backend::APIUtil(profile_, temporary_file_dir_));
   api_util_->AddObserver(this);
 
   metadata_store_.reset(new DriveMetadataStore(
-      GetSyncFileSystemDir(profile_->GetPath()),
+      profile_->GetPath().Append(GetSyncFileSystemDir()),
       content::BrowserThread::GetMessageLoopProxyForThread(
           content::BrowserThread::FILE).get()));
 
diff --git a/chrome/browser/sync_file_system/local/local_file_change_tracker.h b/chrome/browser/sync_file_system/local/local_file_change_tracker.h
index 456a489..93470d1 100644
--- a/chrome/browser/sync_file_system/local/local_file_change_tracker.h
+++ b/chrome/browser/sync_file_system/local/local_file_change_tracker.h
@@ -103,7 +103,6 @@ class LocalFileChangeTracker
   friend class CannedSyncableFileSystem;
   friend class LocalFileChangeTrackerTest;
   friend class LocalFileSyncContext;
-  friend class LocalFileSyncContextTest;
   friend class SyncableFileSystemTest;
 
   struct ChangeInfo {
diff --git a/chrome/browser/sync_file_system/local/local_file_change_tracker_unittest.cc b/chrome/browser/sync_file_system/local/local_file_change_tracker_unittest.cc
index 4a44e76..de0128d 100644
--- a/chrome/browser/sync_file_system/local/local_file_change_tracker_unittest.cc
+++ b/chrome/browser/sync_file_system/local/local_file_change_tracker_unittest.cc
@@ -43,8 +43,7 @@ class LocalFileChangeTrackerTest : public testing::Test {
     file_system_.SetUp();
 
     sync_context_ =
-        new LocalFileSyncContext(base::FilePath(),
-                                 base::MessageLoopProxy::current().get(),
+        new LocalFileSyncContext(base::MessageLoopProxy::current().get(),
                                  base::MessageLoopProxy::current().get());
     ASSERT_EQ(
         sync_file_system::SYNC_STATUS_OK,
diff --git a/chrome/browser/sync_file_system/local/local_file_sync_context.cc b/chrome/browser/sync_file_system/local/local_file_sync_context.cc
index b4f3a03..c8b937a 100644
--- a/chrome/browser/sync_file_system/local/local_file_sync_context.cc
+++ b/chrome/browser/sync_file_system/local/local_file_sync_context.cc
@@ -5,7 +5,6 @@
 #include "chrome/browser/sync_file_system/local/local_file_sync_context.h"
 
 #include "base/bind.h"
-#include "base/file_util.h"
 #include "base/location.h"
 #include "base/platform_file.h"
 #include "base/single_thread_task_runner.h"
@@ -22,7 +21,6 @@
 #include "webkit/browser/fileapi/file_system_file_util.h"
 #include "webkit/browser/fileapi/file_system_operation_context.h"
 #include "webkit/browser/fileapi/file_system_operation_runner.h"
-#include "webkit/common/blob/scoped_file.h"
 #include "webkit/common/fileapi/file_system_util.h"
 
 using fileapi::FileSystemContext;
@@ -39,16 +37,12 @@ const int kMaxConcurrentSyncableOperation = 3;
 const int kNotifyChangesDurationInSec = 1;
 const int kMaxURLsToFetchForLocalSync = 5;
 
-const base::FilePath::CharType kSnapshotDir[] = FILE_PATH_LITERAL("snapshots");
-
 }  // namespace
 
 LocalFileSyncContext::LocalFileSyncContext(
-    const base::FilePath& base_path,
     base::SingleThreadTaskRunner* ui_task_runner,
     base::SingleThreadTaskRunner* io_task_runner)
-    : local_base_path_(base_path.Append(FILE_PATH_LITERAL("local"))),
-      ui_task_runner_(ui_task_runner),
+    : ui_task_runner_(ui_task_runner),
       io_task_runner_(io_task_runner),
       shutdown_on_ui_(false),
       mock_notify_changes_duration_in_sec_(-1) {
@@ -165,12 +159,6 @@ void LocalFileSyncContext::CommitChangeStatusForURL(
     backend->change_tracker()->RemoveMirrorAndCommitChangesForURL(url);
   }
 
-  // We've been keeping it in writing mode, so clear the writing counter
-  // to unblock sync activities.
-  io_task_runner_->PostTask(
-      FROM_HERE, base::Bind(&LocalFileSyncContext::EndWritingOnIOThread,
-                            this, url));
-
   // Call the completion callback on UI thread.
   ui_task_runner_->PostTask(FROM_HERE, done_callback);
 }
@@ -179,8 +167,8 @@ void LocalFileSyncContext::ClearSyncFlagForURL(const FileSystemURL& url) {
   // This is initially called on UI thread and to be relayed to IO thread.
   io_task_runner_->PostTask(
       FROM_HERE,
-      base::Bind(&LocalFileSyncContext::ClearSyncFlagOnIOThread,
-                 this, url, false /* keep_url_in_writing */));
+      base::Bind(&LocalFileSyncContext::EnableWritingOnIOThread,
+                 this, url, true /* may_have_updates */));
 }
 
 void LocalFileSyncContext::PrepareForSync(
@@ -562,10 +550,6 @@ SyncStatusCode LocalFileSyncContext::InitializeChangeTrackerOnFileThread(
        iter != urls.end(); ++iter) {
     origins_with_changes->insert(iter->origin());
   }
-
-  // Creates snapshot directory.
-  file_util::CreateDirectory(local_base_path_.Append(kSnapshotDir));
-
   return status;
 }
 
@@ -649,14 +633,13 @@ void LocalFileSyncContext::TryPrepareForLocalSync(
   DCHECK(urls);
 
   if (shutdown_on_ui_) {
-    callback.Run(SYNC_STATUS_ABORT, LocalFileSyncInfo(),
-                 scoped_ptr<webkit_blob::ScopedFile>());
+    callback.Run(SYNC_STATUS_ABORT, LocalFileSyncInfo());
     return;
   }
 
   if (urls->empty()) {
-    callback.Run(SYNC_STATUS_NO_CHANGE_TO_SYNC, LocalFileSyncInfo(),
-                 scoped_ptr<webkit_blob::ScopedFile>());
+    callback.Run(SYNC_STATUS_NO_CHANGE_TO_SYNC,
+                 LocalFileSyncInfo());
     return;
   }
 
@@ -665,8 +648,9 @@ void LocalFileSyncContext::TryPrepareForLocalSync(
   std::deque<FileSystemURL>* remaining = new std::deque<FileSystemURL>;
   remaining->swap(*urls);
 
+  // TODO(kinuko): Call PrepareForSync with SYNC_SNAPSHOT when it becomes ready.
   PrepareForSync(
-      file_system_context, url, SYNC_SNAPSHOT,
+      file_system_context, url, SYNC_EXCLUSIVE,
       base::Bind(&LocalFileSyncContext::DidTryPrepareForLocalSync,
                  this, make_scoped_refptr(file_system_context),
                  base::Owned(remaining), callback));
@@ -677,11 +661,10 @@ void LocalFileSyncContext::DidTryPrepareForLocalSync(
     std::deque<FileSystemURL>* remaining_urls,
     const LocalFileSyncInfoCallback& callback,
     SyncStatusCode status,
-    const LocalFileSyncInfo& sync_file_info,
-    scoped_ptr<webkit_blob::ScopedFile> snapshot) {
+    const LocalFileSyncInfo& sync_file_info) {
   DCHECK(ui_task_runner_->RunsTasksOnCurrentThread());
   if (status != SYNC_STATUS_FILE_BUSY) {
-    callback.Run(status, sync_file_info, snapshot.Pass());
+    callback.Run(status, sync_file_info);
     return;
   }
   // Recursively call TryPrepareForLocalSync with remaining_urls.
@@ -700,8 +683,7 @@ void LocalFileSyncContext::DidGetWritingStatusForSync(
           RunsTasksOnCurrentThread()) {
     DCHECK(ui_task_runner_->RunsTasksOnCurrentThread());
     if (shutdown_on_ui_) {
-      callback.Run(SYNC_STATUS_ABORT, LocalFileSyncInfo(),
-                   scoped_ptr<webkit_blob::ScopedFile>());
+      callback.Run(SYNC_STATUS_ABORT, LocalFileSyncInfo());
       return;
     }
     file_system_context->default_file_task_runner()->PostTask(
@@ -731,21 +713,9 @@ void LocalFileSyncContext::DidGetWritingStatusForSync(
       url,
       &file_info,
       &platform_path);
-
-  scoped_ptr<webkit_blob::ScopedFile> snapshot;
   if (file_error == base::PLATFORM_FILE_OK && sync_mode == SYNC_SNAPSHOT) {
-    base::FilePath snapshot_path;
-    file_util::CreateTemporaryFileInDir(local_base_path_.Append(kSnapshotDir),
-                                        &snapshot_path);
-    if (base::CopyFile(platform_path, snapshot_path)) {
-      platform_path = snapshot_path;
-      snapshot.reset(new webkit_blob::ScopedFile(
-          snapshot_path,
-          webkit_blob::ScopedFile::DELETE_ON_SCOPE_OUT,
-          file_system_context->default_file_task_runner()));
-    }
+    // TODO(kinuko): creates a snapshot file.
   }
-
   if (status == SYNC_STATUS_OK &&
       file_error != base::PLATFORM_FILE_OK &&
       file_error != base::PLATFORM_FILE_ERROR_NOT_FOUND)
@@ -759,6 +729,7 @@ void LocalFileSyncContext::DidGetWritingStatusForSync(
   else if (file_info.is_directory)
     file_type = SYNC_FILE_TYPE_DIRECTORY;
 
+  // TODO(kinuko): returns the snapshot file path if snapshot is available.
   LocalFileSyncInfo sync_file_info;
   sync_file_info.url = url;
   sync_file_info.local_file_path = platform_path;
@@ -776,24 +747,21 @@ void LocalFileSyncContext::DidGetWritingStatusForSync(
     }
 
     // 'Unlock' the file if sync_mode is not SYNC_EXCLUSIVE.
-    // (But keep it in writing status so that no other sync starts on
-    // the same URL)
     if (sync_mode != SYNC_EXCLUSIVE) {
       io_task_runner_->PostTask(
           FROM_HERE,
-          base::Bind(&LocalFileSyncContext::ClearSyncFlagOnIOThread,
-                     this, url, true /* keep_url_in_writing */));
+          base::Bind(&LocalFileSyncContext::EnableWritingOnIOThread,
+                    this, url, false /* may_have_updates */));
     }
   }
 
   ui_task_runner_->PostTask(FROM_HERE,
-                            base::Bind(callback, status, sync_file_info,
-                                       base::Passed(&snapshot)));
+                            base::Bind(callback, status, sync_file_info));
 }
 
-void LocalFileSyncContext::ClearSyncFlagOnIOThread(
+void LocalFileSyncContext::EnableWritingOnIOThread(
     const FileSystemURL& url,
-    bool keep_url_in_writing) {
+    bool may_have_updates) {
   DCHECK(io_task_runner_->RunsTasksOnCurrentThread());
   if (!sync_status()) {
     // The service might have been shut down.
@@ -801,27 +769,14 @@ void LocalFileSyncContext::ClearSyncFlagOnIOThread(
   }
   sync_status()->EndSyncing(url);
 
-  if (keep_url_in_writing) {
-    // The caller will hold shared lock on this one.
-    sync_status()->StartWriting(url);
+  if (!may_have_updates)
     return;
-  }
 
   // Since a sync has finished the number of changes must have been updated.
   origins_with_pending_changes_.insert(url.origin());
   ScheduleNotifyChangesUpdatedOnIOThread();
 }
 
-void LocalFileSyncContext::EndWritingOnIOThread(
-    const FileSystemURL& url) {
-  DCHECK(io_task_runner_->RunsTasksOnCurrentThread());
-  if (!sync_status()) {
-    // The service might have been shut down.
-    return;
-  }
-  sync_status()->EndWriting(url);
-}
-
 void LocalFileSyncContext::DidApplyRemoteChange(
     const FileSystemURL& url,
     const SyncStatusCallback& callback_on_ui,
@@ -831,7 +786,7 @@ void LocalFileSyncContext::DidApplyRemoteChange(
       FROM_HERE,
       base::Bind(callback_on_ui,
                  PlatformFileErrorToSyncStatusCode(file_error)));
-  ClearSyncFlagOnIOThread(url, false /* keep_url_in_writing */);
+  EnableWritingOnIOThread(url, true /* may_have_updates */);
 }
 
 void LocalFileSyncContext::DidGetFileMetadata(
diff --git a/chrome/browser/sync_file_system/local/local_file_sync_context.h b/chrome/browser/sync_file_system/local/local_file_sync_context.h
index 788721d..7a4cfe7 100644
--- a/chrome/browser/sync_file_system/local/local_file_sync_context.h
+++ b/chrome/browser/sync_file_system/local/local_file_sync_context.h
@@ -33,10 +33,6 @@ class FileSystemContext;
 class FileSystemURL;
 }
 
-namespace webkit_blob {
-class ScopedFile;
-}
-
 namespace sync_file_system {
 
 class FileChange;
@@ -60,17 +56,14 @@ class LocalFileSyncContext
   };
 
   typedef base::Callback<void(
-      SyncStatusCode status,
-      const LocalFileSyncInfo& sync_file_info,
-      scoped_ptr<webkit_blob::ScopedFile> snapshot)>
+      SyncStatusCode status, const LocalFileSyncInfo& sync_file_info)>
           LocalFileSyncInfoCallback;
 
   typedef base::Callback<void(SyncStatusCode status,
                               bool has_pending_changes)>
       HasPendingLocalChangeCallback;
 
-  LocalFileSyncContext(const base::FilePath& base_path,
-                       base::SingleThreadTaskRunner* ui_task_runner,
+  LocalFileSyncContext(base::SingleThreadTaskRunner* ui_task_runner,
                        base::SingleThreadTaskRunner* io_task_runner);
 
   // Initializes |file_system_context| for syncable file operations
@@ -244,8 +237,7 @@ class LocalFileSyncContext
       std::deque<fileapi::FileSystemURL>* remaining_urls,
       const LocalFileSyncInfoCallback& callback,
       SyncStatusCode status,
-      const LocalFileSyncInfo& sync_file_info,
-      scoped_ptr<webkit_blob::ScopedFile> snapshot);
+      const LocalFileSyncInfo& sync_file_info);
 
   // Callback routine for PrepareForSync and GetFileForLocalSync.
   void DidGetWritingStatusForSync(
@@ -255,16 +247,9 @@ class LocalFileSyncContext
       SyncMode sync_mode,
       const LocalFileSyncInfoCallback& callback);
 
-  // Helper routine for sync/writing flag handling, primarily for
-  // ClearSyncFlagForURL but is also called by other internal routines.
-  // If |keep_url_in_writing| is true this increments the writing counter
-  // for |url| (after clearing syncing flag), so that the caller can
-  // continue to hold a shared lock on the URL.
-  // (The counter must be manually decremented by EndWritingOnIOThread
-  // if that's the case)
-  void ClearSyncFlagOnIOThread(const fileapi::FileSystemURL& url,
-                               bool keep_url_in_writing);
-  void EndWritingOnIOThread(const fileapi::FileSystemURL& url);
+  // Helper routine for ClearSyncFlagForURL.
+  void EnableWritingOnIOThread(const fileapi::FileSystemURL& url,
+                               bool may_have_updates);
 
   void DidRemoveExistingEntryForApplyRemoteChange(
       fileapi::FileSystemContext* file_system_context,
@@ -294,8 +279,6 @@ class LocalFileSyncContext
       const StatusCallback& callback,
       base::PlatformFileError error);
 
-  const base::FilePath local_base_path_;
-
   scoped_refptr<base::SingleThreadTaskRunner> ui_task_runner_;
   scoped_refptr<base::SingleThreadTaskRunner> io_task_runner_;
 
diff --git a/chrome/browser/sync_file_system/local/local_file_sync_context_unittest.cc b/chrome/browser/sync_file_system/local/local_file_sync_context_unittest.cc
index 1d3b360..a1ede5a 100644
--- a/chrome/browser/sync_file_system/local/local_file_sync_context_unittest.cc
+++ b/chrome/browser/sync_file_system/local/local_file_sync_context_unittest.cc
@@ -26,7 +26,6 @@
 #include "webkit/browser/fileapi/file_system_context.h"
 #include "webkit/browser/fileapi/file_system_operation_runner.h"
 #include "webkit/browser/fileapi/isolated_context.h"
-#include "webkit/common/blob/scoped_file.h"
 
 #define FPL FILE_PATH_LITERAL
 
@@ -61,7 +60,6 @@ class LocalFileSyncContextTest : public testing::Test {
 
   virtual void SetUp() OVERRIDE {
     RegisterSyncableFileSystem();
-    ASSERT_TRUE(dir_.CreateUniqueTempDir());
 
     ui_task_runner_ = base::MessageLoop::current()->message_loop_proxy();
     io_task_runner_ = BrowserThread::GetMessageLoopProxyForThread(
@@ -76,10 +74,8 @@ class LocalFileSyncContextTest : public testing::Test {
 
   void StartPrepareForSync(FileSystemContext* file_system_context,
                            const FileSystemURL& url,
-                           LocalFileSyncContext::SyncMode sync_mode,
                            SyncFileMetadata* metadata,
-                           FileChangeList* changes,
-                           webkit_blob::ScopedFile* snapshot) {
+                           FileChangeList* changes) {
     ASSERT_TRUE(changes != NULL);
     ASSERT_FALSE(has_inflight_prepare_for_sync_);
     status_ = SYNC_STATUS_UNKNOWN;
@@ -87,49 +83,39 @@ class LocalFileSyncContextTest : public testing::Test {
     sync_context_->PrepareForSync(
         file_system_context,
         url,
-        sync_mode,
+        LocalFileSyncContext::SYNC_EXCLUSIVE,
         base::Bind(&LocalFileSyncContextTest::DidPrepareForSync,
-                   base::Unretained(this), metadata, changes, snapshot));
+                   base::Unretained(this), metadata, changes));
   }
 
   SyncStatusCode PrepareForSync(FileSystemContext* file_system_context,
                                 const FileSystemURL& url,
-                                LocalFileSyncContext::SyncMode sync_mode,
                                 SyncFileMetadata* metadata,
-                                FileChangeList* changes,
-                                webkit_blob::ScopedFile* snapshot) {
-    StartPrepareForSync(file_system_context, url, sync_mode,
-                        metadata, changes, snapshot);
+                                FileChangeList* changes) {
+    StartPrepareForSync(file_system_context, url, metadata, changes);
     base::MessageLoop::current()->Run();
     return status_;
   }
 
-  base::Closure GetPrepareForSyncClosure(
-      FileSystemContext* file_system_context,
-      const FileSystemURL& url,
-      LocalFileSyncContext::SyncMode sync_mode,
-      SyncFileMetadata* metadata,
-      FileChangeList* changes,
-      webkit_blob::ScopedFile* snapshot) {
+  base::Closure GetPrepareForSyncClosure(FileSystemContext* file_system_context,
+                                         const FileSystemURL& url,
+                                         SyncFileMetadata* metadata,
+                                         FileChangeList* changes) {
     return base::Bind(&LocalFileSyncContextTest::StartPrepareForSync,
                       base::Unretained(this),
                       base::Unretained(file_system_context),
-                      url, sync_mode, metadata, changes, snapshot);
+                      url, metadata, changes);
   }
 
   void DidPrepareForSync(SyncFileMetadata* metadata_out,
                          FileChangeList* changes_out,
-                         webkit_blob::ScopedFile* snapshot_out,
                          SyncStatusCode status,
-                         const LocalFileSyncInfo& sync_file_info,
-                         scoped_ptr<webkit_blob::ScopedFile> snapshot) {
+                         const LocalFileSyncInfo& sync_file_info) {
     ASSERT_TRUE(ui_task_runner_->RunsTasksOnCurrentThread());
     has_inflight_prepare_for_sync_ = false;
     status_ = status;
     *metadata_out = sync_file_info.metadata;
     *changes_out = sync_file_info.changes;
-    if (snapshot_out && snapshot)
-      *snapshot_out = snapshot->Pass();
     base::MessageLoop::current()->Quit();
   }
 
@@ -145,9 +131,7 @@ class LocalFileSyncContextTest : public testing::Test {
     SyncFileMetadata metadata;
     FileChangeList changes;
     EXPECT_EQ(SYNC_STATUS_OK,
-              PrepareForSync(file_system_context, url,
-                             LocalFileSyncContext::SYNC_EXCLUSIVE,
-                             &metadata, &changes, NULL));
+              PrepareForSync(file_system_context, url, &metadata, &changes));
     EXPECT_EQ(expected_file_type, metadata.file_type);
 
     status_ = SYNC_STATUS_UNKNOWN;
@@ -222,7 +206,7 @@ class LocalFileSyncContextTest : public testing::Test {
                                          file_task_runner_.get());
     file_system.SetUp();
     sync_context_ = new LocalFileSyncContext(
-        dir_.path(), ui_task_runner_.get(), io_task_runner_.get());
+        ui_task_runner_.get(), io_task_runner_.get());
     ASSERT_EQ(SYNC_STATUS_OK,
               file_system.MaybeInitializeFileSystemContext(
                   sync_context_.get()));
@@ -235,7 +219,7 @@ class LocalFileSyncContextTest : public testing::Test {
     FileChangeList changes;
     EXPECT_EQ(SYNC_STATUS_OK,
               PrepareForSync(file_system.file_system_context(), kFile,
-                             sync_mode, &metadata, &changes, NULL));
+                             &metadata, &changes));
     EXPECT_EQ(1U, changes.size());
     EXPECT_TRUE(changes.list().back().IsFile());
     EXPECT_TRUE(changes.list().back().IsAddOrUpdate());
@@ -265,73 +249,8 @@ class LocalFileSyncContextTest : public testing::Test {
     file_system.TearDown();
   }
 
-  void PrepareForSync_WriteDuringSync(
-      LocalFileSyncContext::SyncMode sync_mode) {
-    CannedSyncableFileSystem file_system(GURL(kOrigin1),
-                                         io_task_runner_.get(),
-                                         file_task_runner_.get());
-    file_system.SetUp();
-    sync_context_ = new LocalFileSyncContext(
-        dir_.path(), ui_task_runner_.get(), io_task_runner_.get());
-    ASSERT_EQ(SYNC_STATUS_OK,
-              file_system.MaybeInitializeFileSystemContext(
-                  sync_context_.get()));
-    ASSERT_EQ(base::PLATFORM_FILE_OK, file_system.OpenFileSystem());
-
-    const FileSystemURL kFile(file_system.URL("file"));
-    EXPECT_EQ(base::PLATFORM_FILE_OK, file_system.CreateFile(kFile));
-
-    SyncFileMetadata metadata;
-    FileChangeList changes;
-    webkit_blob::ScopedFile snapshot;
-    EXPECT_EQ(SYNC_STATUS_OK,
-              PrepareForSync(file_system.file_system_context(), kFile,
-                             sync_mode, &metadata, &changes, &snapshot));
-    EXPECT_EQ(1U, changes.size());
-    EXPECT_TRUE(changes.list().back().IsFile());
-    EXPECT_TRUE(changes.list().back().IsAddOrUpdate());
-
-    EXPECT_EQ(sync_mode == LocalFileSyncContext::SYNC_SNAPSHOT,
-              !snapshot.path().empty());
-
-    // Tracker keeps same set of changes.
-    file_system.GetChangesForURLInTracker(kFile, &changes);
-    EXPECT_EQ(1U, changes.size());
-    EXPECT_TRUE(changes.list().back().IsFile());
-    EXPECT_TRUE(changes.list().back().IsAddOrUpdate());
-
-    StartModifyFileOnIOThread(&file_system, kFile);
-
-    if (sync_mode == LocalFileSyncContext::SYNC_SNAPSHOT) {
-      // Write should succeed.
-      EXPECT_EQ(base::PLATFORM_FILE_OK, WaitUntilModifyFileIsDone());
-    } else {
-      base::MessageLoop::current()->RunUntilIdle();
-      EXPECT_FALSE(async_modify_finished_);
-    }
-
-    SimulateFinishSync(file_system.file_system_context(), kFile,
-                       SYNC_STATUS_OK);
-
-    EXPECT_EQ(base::PLATFORM_FILE_OK, WaitUntilModifyFileIsDone());
-
-    // Sync succeeded, but the other change that was made during or
-    // after sync is recorded.
-    file_system.GetChangesForURLInTracker(kFile, &changes);
-    EXPECT_EQ(1U, changes.size());
-    EXPECT_TRUE(changes.list().back().IsFile());
-    EXPECT_TRUE(changes.list().back().IsAddOrUpdate());
-
-    sync_context_->ShutdownOnUIThread();
-    sync_context_ = NULL;
-
-    file_system.TearDown();
-  }
-
   ScopedEnableSyncFSDirectoryOperation enable_directory_operation_;
 
-  base::ScopedTempDir dir_;
-
   // These need to remain until the very end.
   content::TestBrowserThreadBundle thread_bundle_;
 
@@ -348,9 +267,8 @@ class LocalFileSyncContextTest : public testing::Test {
 };
 
 TEST_F(LocalFileSyncContextTest, ConstructAndDestruct) {
-  sync_context_ =
-      new LocalFileSyncContext(
-          dir_.path(), ui_task_runner_.get(), io_task_runner_.get());
+  sync_context_ = new LocalFileSyncContext(
+      ui_task_runner_.get(), io_task_runner_.get());
   sync_context_->ShutdownOnUIThread();
 }
 
@@ -361,7 +279,7 @@ TEST_F(LocalFileSyncContextTest, InitializeFileSystemContext) {
   file_system.SetUp();
 
   sync_context_ = new LocalFileSyncContext(
-      dir_.path(), ui_task_runner_.get(), io_task_runner_.get());
+      ui_task_runner_.get(), io_task_runner_.get());
 
   // Initializes file_system using |sync_context_|.
   EXPECT_EQ(SYNC_STATUS_OK,
@@ -406,7 +324,7 @@ TEST_F(LocalFileSyncContextTest, MultipleFileSystemContexts) {
   file_system2.SetUp();
 
   sync_context_ = new LocalFileSyncContext(
-      dir_.path(), ui_task_runner_.get(), io_task_runner_.get());
+      ui_task_runner_.get(), io_task_runner_.get());
 
   // Initializes file_system1 and file_system2.
   EXPECT_EQ(SYNC_STATUS_OK,
@@ -453,8 +371,7 @@ TEST_F(LocalFileSyncContextTest, MultipleFileSystemContexts) {
   FileChangeList changes;
   EXPECT_EQ(SYNC_STATUS_OK,
             PrepareForSync(file_system1.file_system_context(), kURL1,
-                           LocalFileSyncContext::SYNC_EXCLUSIVE,
-                           &metadata, &changes, NULL));
+                           &metadata, &changes));
   EXPECT_EQ(1U, changes.size());
   EXPECT_TRUE(changes.list().back().IsFile());
   EXPECT_TRUE(changes.list().back().IsAddOrUpdate());
@@ -464,8 +381,7 @@ TEST_F(LocalFileSyncContextTest, MultipleFileSystemContexts) {
   changes.clear();
   EXPECT_EQ(SYNC_STATUS_OK,
             PrepareForSync(file_system2.file_system_context(), kURL2,
-                           LocalFileSyncContext::SYNC_EXCLUSIVE,
-                           &metadata, &changes, NULL));
+                           &metadata, &changes));
   EXPECT_EQ(1U, changes.size());
   EXPECT_FALSE(changes.list().back().IsFile());
   EXPECT_TRUE(changes.list().back().IsAddOrUpdate());
@@ -499,14 +415,6 @@ TEST_F(LocalFileSyncContextTest, PrepareSync_SyncFailure_Snapshot) {
                        SYNC_STATUS_FAILED);
 }
 
-TEST_F(LocalFileSyncContextTest, PrepareSync_WriteDuringSync_Exclusive) {
-  PrepareForSync_WriteDuringSync(LocalFileSyncContext::SYNC_EXCLUSIVE);
-}
-
-TEST_F(LocalFileSyncContextTest, PrepareSync_WriteDuringSync_Snapshot) {
-  PrepareForSync_WriteDuringSync(LocalFileSyncContext::SYNC_SNAPSHOT);
-}
-
 // LocalFileSyncContextTest.PrepareSyncWhileWriting is flaky on android.
 // http://crbug.com/239793
 #if defined(OS_ANDROID)
@@ -520,7 +428,7 @@ TEST_F(LocalFileSyncContextTest, MAYBE_PrepareSyncWhileWriting) {
                                        file_task_runner_.get());
   file_system.SetUp();
   sync_context_ = new LocalFileSyncContext(
-      dir_.path(), ui_task_runner_.get(), io_task_runner_.get());
+      ui_task_runner_.get(), io_task_runner_.get());
   EXPECT_EQ(SYNC_STATUS_OK,
             file_system.MaybeInitializeFileSystemContext(sync_context_.get()));
 
@@ -539,9 +447,8 @@ TEST_F(LocalFileSyncContextTest, MAYBE_PrepareSyncWhileWriting) {
   metadata.file_type = SYNC_FILE_TYPE_UNKNOWN;
   FileChangeList changes;
   EXPECT_EQ(SYNC_STATUS_FILE_BUSY,
-            PrepareForSync(file_system.file_system_context(), kURL1,
-                           LocalFileSyncContext::SYNC_EXCLUSIVE,
-                           &metadata, &changes, NULL));
+            PrepareForSync(file_system.file_system_context(),
+                           kURL1, &metadata, &changes));
   EXPECT_EQ(SYNC_FILE_TYPE_FILE, metadata.file_type);
 
   // Register PrepareForSync method to be invoked when kURL1 becomes
@@ -550,9 +457,8 @@ TEST_F(LocalFileSyncContextTest, MAYBE_PrepareSyncWhileWriting) {
   metadata.file_type = SYNC_FILE_TYPE_UNKNOWN;
   changes.clear();
   sync_context_->RegisterURLForWaitingSync(
-      kURL1, GetPrepareForSyncClosure(file_system.file_system_context(), kURL1,
-                                      LocalFileSyncContext::SYNC_EXCLUSIVE,
-                                      &metadata, &changes, NULL));
+      kURL1, GetPrepareForSyncClosure(file_system.file_system_context(),
+                                      kURL1, &metadata, &changes));
 
   // Wait for the completion.
   EXPECT_EQ(base::PLATFORM_FILE_OK, WaitUntilModifyFileIsDone());
@@ -582,7 +488,7 @@ TEST_F(LocalFileSyncContextTest, ApplyRemoteChangeForDeletion) {
   file_system.SetUp();
 
   sync_context_ = new LocalFileSyncContext(
-      dir_.path(), ui_task_runner_.get(), io_task_runner_.get());
+      ui_task_runner_.get(), io_task_runner_.get());
   ASSERT_EQ(SYNC_STATUS_OK,
             file_system.MaybeInitializeFileSystemContext(sync_context_.get()));
   ASSERT_EQ(base::PLATFORM_FILE_OK, file_system.OpenFileSystem());
@@ -671,7 +577,7 @@ TEST_F(LocalFileSyncContextTest, ApplyRemoteChangeForAddOrUpdate) {
   file_system.SetUp();
 
   sync_context_ = new LocalFileSyncContext(
-      dir_.path(), ui_task_runner_.get(), io_task_runner_.get());
+      ui_task_runner_.get(), io_task_runner_.get());
   ASSERT_EQ(SYNC_STATUS_OK,
             file_system.MaybeInitializeFileSystemContext(sync_context_.get()));
   ASSERT_EQ(base::PLATFORM_FILE_OK, file_system.OpenFileSystem());
@@ -820,7 +726,7 @@ TEST_F(LocalFileSyncContextTest, ApplyRemoteChangeForAddOrUpdate_NoParent) {
   file_system.SetUp();
 
   sync_context_ = new LocalFileSyncContext(
-      dir_.path(), ui_task_runner_.get(), io_task_runner_.get());
+      ui_task_runner_.get(), io_task_runner_.get());
   ASSERT_EQ(SYNC_STATUS_OK,
             file_system.MaybeInitializeFileSystemContext(sync_context_.get()));
   ASSERT_EQ(base::PLATFORM_FILE_OK, file_system.OpenFileSystem());
diff --git a/chrome/browser/sync_file_system/local/local_file_sync_service.cc b/chrome/browser/sync_file_system/local/local_file_sync_service.cc
index 8a987b8..33fbb34 100644
--- a/chrome/browser/sync_file_system/local/local_file_sync_service.cc
+++ b/chrome/browser/sync_file_system/local/local_file_sync_service.cc
@@ -22,7 +22,6 @@
 #include "url/gurl.h"
 #include "webkit/browser/fileapi/file_system_context.h"
 #include "webkit/browser/fileapi/file_system_url.h"
-#include "webkit/common/blob/scoped_file.h"
 
 using content::BrowserThread;
 using fileapi::FileSystemURL;
@@ -34,8 +33,7 @@ namespace {
 void PrepareForProcessRemoteChangeCallbackAdapter(
     const RemoteChangeProcessor::PrepareChangeCallback& callback,
     SyncStatusCode status,
-    const LocalFileSyncInfo& sync_file_info,
-    scoped_ptr<webkit_blob::ScopedFile> snapshot) {
+    const LocalFileSyncInfo& sync_file_info) {
   callback.Run(status, sync_file_info.metadata, sync_file_info.changes);
 }
 
@@ -99,7 +97,6 @@ void LocalFileSyncService::OriginChangeMap::SetOriginEnabled(
 LocalFileSyncService::LocalFileSyncService(Profile* profile)
     : profile_(profile),
       sync_context_(new LocalFileSyncContext(
-          profile_->GetPath(),
           BrowserThread::GetMessageLoopProxyForThread(BrowserThread::UI).get(),
           BrowserThread::GetMessageLoopProxyForThread(BrowserThread::IO)
               .get())),
@@ -365,8 +362,7 @@ void LocalFileSyncService::RunLocalSyncCallback(
 
 void LocalFileSyncService::DidGetFileForLocalSync(
     SyncStatusCode status,
-    const LocalFileSyncInfo& sync_file_info,
-    scoped_ptr<webkit_blob::ScopedFile> snapshot) {
+    const LocalFileSyncInfo& sync_file_info) {
   DCHECK(!local_sync_callback_.is_null());
   if (status != SYNC_STATUS_OK) {
     RunLocalSyncCallback(status, sync_file_info.url);
@@ -390,12 +386,11 @@ void LocalFileSyncService::DidGetFileForLocalSync(
       sync_file_info.metadata,
       sync_file_info.url,
       base::Bind(&LocalFileSyncService::ProcessNextChangeForURL,
-                 AsWeakPtr(), base::Passed(&snapshot), sync_file_info,
+                 AsWeakPtr(), sync_file_info,
                  next_change, sync_file_info.changes.PopAndGetNewList()));
 }
 
 void LocalFileSyncService::ProcessNextChangeForURL(
-    scoped_ptr<webkit_blob::ScopedFile> snapshot,
     const LocalFileSyncInfo& sync_file_info,
     const FileChange& processed_change,
     const FileChangeList& changes,
@@ -412,8 +407,7 @@ void LocalFileSyncService::ProcessNextChangeForURL(
         sync_file_info.metadata,
         sync_file_info.url,
         base::Bind(&LocalFileSyncService::ProcessNextChangeForURL,
-                   AsWeakPtr(), base::Passed(&snapshot),
-                   sync_file_info, processed_change, changes));
+                   AsWeakPtr(), sync_file_info, processed_change, changes));
     return;
   }
 
@@ -440,7 +434,7 @@ void LocalFileSyncService::ProcessNextChangeForURL(
       sync_file_info.metadata,
       url,
       base::Bind(&LocalFileSyncService::ProcessNextChangeForURL,
-                 AsWeakPtr(), base::Passed(&snapshot), sync_file_info,
+                 AsWeakPtr(), sync_file_info,
                  next_change, changes.PopAndGetNewList()));
 }
 
diff --git a/chrome/browser/sync_file_system/local/local_file_sync_service.h b/chrome/browser/sync_file_system/local/local_file_sync_service.h
index b72f66e..7da29c6 100644
--- a/chrome/browser/sync_file_system/local/local_file_sync_service.h
+++ b/chrome/browser/sync_file_system/local/local_file_sync_service.h
@@ -26,10 +26,6 @@ namespace fileapi {
 class FileSystemContext;
 }
 
-namespace webkit_blob {
-class ScopedFile;
-}
-
 namespace sync_file_system {
 
 class FileChange;
@@ -185,10 +181,8 @@ class LocalFileSyncService
   // Callbacks for ProcessLocalChange.
   void DidGetFileForLocalSync(
       SyncStatusCode status,
-      const LocalFileSyncInfo& sync_file_info,
-      scoped_ptr<webkit_blob::ScopedFile> snapshot);
+      const LocalFileSyncInfo& sync_file_info);
   void ProcessNextChangeForURL(
-      scoped_ptr<webkit_blob::ScopedFile> snapshot,
       const LocalFileSyncInfo& sync_file_info,
       const FileChange& last_change,
       const FileChangeList& changes,
diff --git a/chrome/browser/sync_file_system/local/local_file_sync_service_unittest.cc b/chrome/browser/sync_file_system/local/local_file_sync_service_unittest.cc
index 035e03c..499ea67 100644
--- a/chrome/browser/sync_file_system/local/local_file_sync_service_unittest.cc
+++ b/chrome/browser/sync_file_system/local/local_file_sync_service_unittest.cc
@@ -321,12 +321,10 @@ TEST_F(LocalFileSyncServiceTest, ProcessLocalChange_CreateFile) {
 
   base::RunLoop run_loop;
 
-  // We should get called OnSyncEnabled and OnWriteEnabled on kFile.
-  // (OnWriteEnabled is called because we release lock before returning
-  // from ApplyLocalChange)
+  // We should get called OnSyncEnabled on kFile.
   StrictMock<MockSyncStatusObserver> status_observer;
-  EXPECT_CALL(status_observer, OnSyncEnabled(kFile)).Times(AtLeast(1));
-  EXPECT_CALL(status_observer, OnWriteEnabled(kFile)).Times(AtLeast(1));
+  EXPECT_CALL(status_observer, OnSyncEnabled(kFile))
+      .Times(AtLeast(1));
   file_system_->AddSyncStatusObserver(&status_observer);
 
   // Creates and writes into a file.
@@ -334,7 +332,7 @@ TEST_F(LocalFileSyncServiceTest, ProcessLocalChange_CreateFile) {
   EXPECT_EQ(kTestFileDataSize,
             file_system_->WriteString(kFile, std::string(kTestFileData)));
 
-  // Retrieve the expected file info.
+  // Retrieve the expected platform_path.
   base::PlatformFileInfo info;
   base::FilePath platform_path;
   EXPECT_EQ(base::PLATFORM_FILE_OK,
@@ -355,7 +353,7 @@ TEST_F(LocalFileSyncServiceTest, ProcessLocalChange_CreateFile) {
   const FileChange change(FileChange::FILE_CHANGE_ADD_OR_UPDATE,
                           SYNC_FILE_TYPE_FILE);
   EXPECT_CALL(local_change_processor,
-              ApplyLocalChange(change, _, metadata, kFile, _))
+              ApplyLocalChange(change, platform_path, metadata, kFile, _))
       .WillOnce(MockStatusCallback(SYNC_STATUS_OK));
 
   local_service_->SetLocalChangeProcessor(&local_change_processor);
@@ -377,8 +375,8 @@ TEST_F(LocalFileSyncServiceTest, ProcessLocalChange_CreateAndRemoveFile) {
 
   // We should get called OnSyncEnabled and OnWriteEnabled on kFile.
   StrictMock<MockSyncStatusObserver> status_observer;
-  EXPECT_CALL(status_observer, OnSyncEnabled(kFile)).Times(AtLeast(1));
-  EXPECT_CALL(status_observer, OnWriteEnabled(kFile)).Times(AtLeast(1));
+  EXPECT_CALL(status_observer, OnSyncEnabled(kFile))
+      .Times(AtLeast(1));
   file_system_->AddSyncStatusObserver(&status_observer);
 
   // Creates and then deletes a file.
@@ -467,10 +465,6 @@ TEST_F(LocalFileSyncServiceTest, ProcessLocalChange_MultipleChanges) {
       .WillOnce(MockStatusCallbackAndRecordChange(SYNC_STATUS_OK, &changes))
       .WillOnce(MockStatusCallbackAndRecordChange(SYNC_STATUS_OK, &changes));
   local_service_->SetLocalChangeProcessor(&local_change_processor);
-
-  // OnWriteEnabled will be notified on kPath.
-  EXPECT_CALL(status_observer, OnWriteEnabled(kPath)).Times(AtLeast(1));
-
   local_service_->ProcessLocalChange(
       base::Bind(&OnSyncCompleted, FROM_HERE, run_loop.QuitClosure(),
                  SYNC_STATUS_OK, kPath));
diff --git a/chrome/browser/sync_file_system/local/syncable_file_operation_runner_unittest.cc b/chrome/browser/sync_file_system/local/syncable_file_operation_runner_unittest.cc
index 112ad95..2f49faa 100644
--- a/chrome/browser/sync_file_system/local/syncable_file_operation_runner_unittest.cc
+++ b/chrome/browser/sync_file_system/local/syncable_file_operation_runner_unittest.cc
@@ -60,10 +60,9 @@ class SyncableFileOperationRunnerTest : public testing::Test {
   virtual void SetUp() OVERRIDE {
     ASSERT_TRUE(dir_.CreateUniqueTempDir());
     file_system_.SetUp();
-    sync_context_ = new LocalFileSyncContext(
-        dir_.path(),
-        base::MessageLoopProxy::current().get(),
-        base::MessageLoopProxy::current().get());
+    sync_context_ =
+        new LocalFileSyncContext(base::MessageLoopProxy::current().get(),
+                                 base::MessageLoopProxy::current().get());
     ASSERT_EQ(
         SYNC_STATUS_OK,
         file_system_.MaybeInitializeFileSystemContext(sync_context_.get()));
diff --git a/chrome/browser/sync_file_system/local/syncable_file_system_unittest.cc b/chrome/browser/sync_file_system/local/syncable_file_system_unittest.cc
index e4a7524..9e5da42 100644
--- a/chrome/browser/sync_file_system/local/syncable_file_system_unittest.cc
+++ b/chrome/browser/sync_file_system/local/syncable_file_system_unittest.cc
@@ -39,13 +39,10 @@ class SyncableFileSystemTest : public testing::Test {
         weak_factory_(this) {}
 
   virtual void SetUp() {
-    ASSERT_TRUE(data_dir_.CreateUniqueTempDir());
-
     file_system_.SetUp();
 
     sync_context_ =
-        new LocalFileSyncContext(data_dir_.path(),
-                                 base::MessageLoopProxy::current().get(),
+        new LocalFileSyncContext(base::MessageLoopProxy::current().get(),
                                  base::MessageLoopProxy::current().get());
     ASSERT_EQ(
         sync_file_system::SYNC_STATUS_OK,
diff --git a/chrome/browser/sync_file_system/syncable_file_system_util.cc b/chrome/browser/sync_file_system/syncable_file_system_util.cc
index d4338e8..a6b2550 100644
--- a/chrome/browser/sync_file_system/syncable_file_system_util.cc
+++ b/chrome/browser/sync_file_system/syncable_file_system_util.cc
@@ -28,11 +28,6 @@ const char kEnableSyncFSDirectoryOperation[] =
 const char kSyncableMountName[] = "syncfs";
 const char kSyncableMountNameForInternalSync[] = "syncfs-internal";
 
-const base::FilePath::CharType kSyncFileSystemDir[] =
-    FILE_PATH_LITERAL("Sync FileSystem");
-const base::FilePath::CharType kSyncFileSystemDirDev[] =
-    FILE_PATH_LITERAL("Sync FileSystem Dev");
-
 bool is_directory_operation_enabled = false;
 
 }  // namespace
@@ -112,12 +107,6 @@ bool IsSyncFSDirectoryOperationEnabled() {
           kEnableSyncFSDirectoryOperation);
 }
 
-base::FilePath GetSyncFileSystemDir(const base::FilePath& profile_base_dir) {
-  return profile_base_dir.Append(
-      IsSyncFSDirectoryOperationEnabled() ? kSyncFileSystemDirDev
-                                          : kSyncFileSystemDir);
-}
-
 ScopedEnableSyncFSDirectoryOperation::ScopedEnableSyncFSDirectoryOperation() {
   was_enabled_ = IsSyncFSDirectoryOperationEnabled();
   SetEnableSyncFSDirectoryOperation(true);
diff --git a/chrome/browser/sync_file_system/syncable_file_system_util.h b/chrome/browser/sync_file_system/syncable_file_system_util.h
index 3cce3ad..408f72c 100644
--- a/chrome/browser/sync_file_system/syncable_file_system_util.h
+++ b/chrome/browser/sync_file_system/syncable_file_system_util.h
@@ -85,9 +85,6 @@ void SetEnableSyncFSDirectoryOperation(bool flag);
 // away when we fully support directory operations. (http://crbug.com/161442)
 bool IsSyncFSDirectoryOperationEnabled();
 
-// Returns SyncFileSystem sub-directory path.
-base::FilePath GetSyncFileSystemDir(const base::FilePath& profile_base_dir);
-
 // Enables directory operation for syncable filesystems temporarily for testing.
 class ScopedEnableSyncFSDirectoryOperation {
  public:
diff --git a/chrome/browser/sync_file_system/syncable_file_system_util_unittest.cc b/chrome/browser/sync_file_system/syncable_file_system_util_unittest.cc
index 31bc00d..3cb27ec 100644
--- a/chrome/browser/sync_file_system/syncable_file_system_util_unittest.cc
+++ b/chrome/browser/sync_file_system/syncable_file_system_util_unittest.cc
@@ -4,7 +4,6 @@
 
 #include "chrome/browser/sync_file_system/syncable_file_system_util.h"
 
-#include "base/files/scoped_temp_dir.h"
 #include "base/logging.h"
 #include "base/message_loop/message_loop.h"
 #include "base/message_loop/message_loop_proxy.h"