[Media Galleries] Lazily initialize the storage monitor.

chrome/browser/storage_monitor/storage_monitor.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/storage_monitor/storage_monitor.h"
 
 #include "base/stl_util.h"
 #include "base/utf_string_conversions.h"
 #include "chrome/browser/storage_monitor/removable_storage_observer.h"
 #include "chrome/browser/storage_monitor/transient_device_ids.h"
@@ skipping 44 matching lines @@
   base::AutoLock lock(storage_lock_);
   for (RemovableStorageMap::const_iterator it = storage_map_.begin();
        it != storage_map_.end();
        ++it) {
     results.push_back(it->second);
   }
   return results;
 }
 
 void StorageMonitor::Initialize(base::Closure callback) {
   if (initialized_) {

[vandebo (ex-Chrome), 2013/05/31 18:05:03]

Add a check that this is only called from a single thread.  Otherwise we need a
lock here.

[Greg Billock, 2013/06/01 01:48:46]

There's a note in the header. I think I tried a check here in the
make-async-init-possible change, but it makes the tests a lot more complicated
-- the unit test thread doesn't identify itself as the UI thread, so we'd have
to pull in some machinery. Let's do that separately if we need to.

[vandebo (ex-Chrome), 2013/06/01 15:47:24]

I think you can use base/threading/thread_checker.h  Didn't mention it last time
because I couldn't remember the name at the time.

[Greg Billock, 2013/06/03 15:30:57]

Added. We'll see if the bots complain.

     if (!callback.is_null())
       callback.Run();
     return;
   }
 
   if (!callback.is_null()) {
     on_initialize_callbacks_.push_back(callback);
   }
 
+  if (initializing_)
+    return;
+
+  initializing_ = true;
   Init();
 }
 
 bool StorageMonitor::IsInitialized() {
   return initialized_;
 }
 
 void StorageMonitor::AddObserver(RemovableStorageObserver* obs) {
   observer_list_->AddObserver(obs);
 }
@@ skipping 16 matching lines @@
 void StorageMonitor::EjectDevice(
     const std::string& device_id,
     base::Callback<void(EjectStatus)> callback) {
   // Platform-specific implementations will override this method to
   // perform actual device ejection.
   callback.Run(EJECT_FAILURE);
 }
 
 StorageMonitor::StorageMonitor()
     : observer_list_(new ObserverListThreadSafe<RemovableStorageObserver>()),
+      initializing_(false),
       initialized_(false),
       transient_device_ids_(new TransientDeviceIds) {
   receiver_.reset(new ReceiverImpl(this));
 
   DCHECK(!g_storage_monitor);
   g_storage_monitor = this;
 }
 
 StorageMonitor::~StorageMonitor() {
   g_storage_monitor = NULL;
@@ skipping 45 matching lines @@
     info = it->second;
     storage_map_.erase(it);
   }
 
   DVLOG(1) << "RemovableStorageDetached for id " << id;
   observer_list_->Notify(
       &RemovableStorageObserver::OnRemovableStorageDetached, info);
 }
 
 }  // namespace chrome