Type conversion fixes, components/ edition.

components/storage_monitor/test_volume_mount_watcher_win.cc

Index: components/storage_monitor/test_volume_mount_watcher_win.cc
diff --git a/components/storage_monitor/test_volume_mount_watcher_win.cc b/components/storage_monitor/test_volume_mount_watcher_win.cc
index 746af6c41e16075be07128444aed12a22a7c3e82..77ea57b282f8557a411400a89fcd90d1ec74314b 100644
--- a/components/storage_monitor/test_volume_mount_watcher_win.cc
+++ b/components/storage_monitor/test_volume_mount_watcher_win.cc
@@ -62,7 +62,8 @@ bool GetMassStorageDeviceDetails(const base::FilePath& device_path,
   base::FilePath path(device_path);
   if (device_path.value().length() > 3)
     path = base::FilePath(device_path.value().substr(0, 3));
-  if (path.value()[0] < L'A' || path.value()[0] > L'Z')
+  base::FilePath::CharType drive_letter = path.value()[0];
+  if (drive_letter < L'A' || drive_letter > L'Z')
     return false;
 
   StorageInfo::Type type = StorageInfo::FIXED_MASS_STORAGE;
@@ -73,7 +74,7 @@ bool GetMassStorageDeviceDetails(const base::FilePath& device_path,
   }
   std::string unique_id =
       "\\\\?\\Volume{00000000-0000-0000-0000-000000000000}\\";
-  unique_id[11] = device_path.value()[0];
+  unique_id[11] = static_cast<char>(drive_letter);
   std::string device_id = StorageInfo::MakeDeviceId(type, unique_id);
   base::string16 storage_label = path.Append(L" Drive").LossyDisplayName();
   *info = StorageInfo(device_id, path.value(), storage_label, base::string16(),