Moved JsonPrefStore to use SequencedWorkerPool

chrome/browser/profiles/profile_impl.cc

 // Copyright (c) 2012 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "chrome/browser/profiles/profile_impl.h"
 
 #include "base/bind.h"
 #include "base/command_line.h"
 #include "base/compiler_specific.h"
 #include "base/environment.h"
 #include "base/file_path.h"
 #include "base/file_util.h"
 #include "base/memory/scoped_ptr.h"
 #include "base/path_service.h"
 #include "base/string_number_conversions.h"
 #include "base/string_tokenizer.h"
 #include "base/string_util.h"
 #include "base/stringprintf.h"
+#include "base/threading/sequenced_worker_pool.h"
 #include "base/utf_string_conversions.h"
 #include "base/version.h"
 #include "chrome/browser/autocomplete/autocomplete_classifier.h"
 #include "chrome/browser/background/background_contents_service_factory.h"
 #include "chrome/browser/background/background_mode_manager.h"
 #include "chrome/browser/browser_process.h"
 #include "chrome/browser/chrome_plugin_service_filter.h"
 #include "chrome/browser/content_settings/cookie_settings.h"
 #include "chrome/browser/content_settings/host_content_settings_map.h"
 #include "chrome/browser/custom_handlers/protocol_handler_registry.h"
@@ skipping 174 matching lines @@
 }
 
 }  // namespace
 
 // static
 Profile* Profile::CreateProfile(const FilePath& path,
                                 Delegate* delegate,
                                 CreateMode create_mode) {
   if (create_mode == CREATE_MODE_ASYNCHRONOUS) {
     DCHECK(delegate);
-    // This is safe while all file operations are done on the FILE thread.
-    BrowserThread::PostTask(
-        BrowserThread::FILE, FROM_HERE,
-        base::Bind(&CreateDirectoryNoResult, path));
+    // We need to make sure that profile directory is created on the same
+    // blocking pool where we will run all its important file serialization
+    // tasks (i.e. JsonPrefStore).
+    scoped_refptr<base::SequencedTaskRunner> task_runner =
+        BrowserThread::GetBlockingPool()->
+          GetSequencedTaskRunnerWithShutdownBehavior(
+              BrowserThread::GetBlockingPool()->GetNamedSequenceToken(
+                  path.AsUTF8Unsafe()),

[willchan no longer on Chromium, 2012/10/11 23:19:31]

The only thing that makes me feel nervous about this is the lack of enforcement
that the different requests all use this token. Where's the JsonPrefStore
created? Can we pass this specific SequencedTaskRunner to it somehow to enforce
that even if this token changes, they both end up using the same token?
Otherwise it feels a bit fragile.

[zel, 2012/10/12 23:15:32]

I have isolated SequencedTaskRunner and shared it for profile creation, this
unfortunately introduces two factory methods for JSonPrefStore again... PTAL

+              base::SequencedWorkerPool::BLOCK_SHUTDOWN);
+    task_runner->PostTask(FROM_HERE,
+                          base::Bind(&CreateDirectoryNoResult, path));
   } else if (create_mode == CREATE_MODE_SYNCHRONOUS) {
     if (!file_util::PathExists(path)) {
       // TODO(tc): http://b/1094718 Bad things happen if we can't write to the
       // profile directory.  We should eventually be able to run in this
       // situation.
       if (!file_util::CreateDirectory(path))
         return NULL;
     }
   } else {
     NOTREACHED();
@@ skipping 914 matching lines @@
   if (!path.empty())
     *cache_path = path;
   *max_size = is_media_context ? prefs_->GetInteger(prefs::kMediaCacheSize) :
                                  prefs_->GetInteger(prefs::kDiskCacheSize);
 }
 
 base::Callback<ChromeURLDataManagerBackend*(void)>
     ProfileImpl::GetChromeURLDataManagerBackendGetter() const {
   return io_data_.GetChromeURLDataManagerBackendGetter();
 }