[Media Gallery] Added code to support mtp device media file system on Windows.

chrome/browser/system_monitor/removable_device_notifications_window_win.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/system_monitor/removable_device_notifications_window_win.h"
 
 #include <windows.h>
 #include <dbt.h>
 #include <fileapi.h>
 
+#include "base/threading/sequenced_worker_pool.h"
 #include "base/win/wrapped_window_proc.h"
 #include "chrome/browser/system_monitor/media_storage_util.h"
 #include "chrome/browser/system_monitor/portable_device_watcher_win.h"
 #include "chrome/browser/system_monitor/removable_device_constants.h"
 #include "chrome/browser/system_monitor/volume_mount_watcher_win.h"
+#include "content/public/browser/browser_thread.h"
 
 namespace chrome {
 
 namespace {
 
 const char16 kWindowClassName[] = L"Chrome_RemovableDeviceNotificationWindow";
 
 RemovableDeviceNotificationsWindowWin*
     g_removable_device_notifications_window_win = NULL;
 
@@ skipping 99 matching lines @@
   }
   return true;
 }
 
 uint64 RemovableDeviceNotificationsWindowWin::GetStorageSize(
     const std::string& location) const {
   NOTIMPLEMENTED();
   return 0ULL;
 }
 
+bool RemovableDeviceNotificationsWindowWin::GetMTPStorageInfoFromDeviceId(
+    const std::string& storage_device_id,
+    string16* device_location,
+    string16* storage_object_id) const {
+  DCHECK(content::BrowserThread::GetBlockingPool()->RunsTasksOnCurrentThread());

[Peter Kasting, 2012/12/21 18:13:30]

Doesn't the rest of this class run on the UI thread?  How is this safe?

[kmadhusu, 2013/01/02 19:48:31]

I thought about this. There is a small chance of destructing
|portable_device_watcher_| on the UI thread while it is being accessed here on
the blocking thread. In order to avoid that I need to introduce another lock in
this class.

A better solution is to call this function on the UI thread. Made changes to
block the MTPDeviceDelegateImplWin task runner until we get the MTP storage
details from the UI thread.

+  MediaStorageUtil::Type type;
+  MediaStorageUtil::CrackDeviceId(storage_device_id, &type, NULL);
+  return ((type == MediaStorageUtil::MTP_OR_PTP) &&
+      portable_device_watcher_->GetMTPStorageInfoFromDeviceId(
+          storage_device_id, device_location, storage_object_id));
+}
+
 // static
 LRESULT CALLBACK RemovableDeviceNotificationsWindowWin::WndProcThunk(
     HWND hwnd, UINT message, WPARAM wparam, LPARAM lparam) {
   RemovableDeviceNotificationsWindowWin* msg_wnd =
       reinterpret_cast<RemovableDeviceNotificationsWindowWin*>(
           GetWindowLongPtr(hwnd, GWLP_USERDATA));
   if (msg_wnd)
     return msg_wnd->WndProc(hwnd, message, wparam, lparam);
   return ::DefWindowProc(hwnd, message, wparam, lparam);
 }
@@ skipping 27 matching lines @@
   portable_device_watcher_->OnWindowMessage(event_type, data);
 }
 
 // static
 RemovableStorageNotifications* RemovableStorageNotifications::GetInstance() {
   DCHECK(g_removable_device_notifications_window_win);
   return g_removable_device_notifications_window_win;
 }
 
 }  // namespace chrome