Convert //chrome from scoped_ptr to std::unique_ptr

chrome/utility/image_writer/disk_unmounter_mac.cc

Index: chrome/utility/image_writer/disk_unmounter_mac.cc
diff --git a/chrome/utility/image_writer/disk_unmounter_mac.cc b/chrome/utility/image_writer/disk_unmounter_mac.cc
index 8d3155a2955fc3654a0ed821e96724d8eae18f0a..7f2777cfb775c1aad1220e5ba8adf009125cb0dc 100644
--- a/chrome/utility/image_writer/disk_unmounter_mac.cc
+++ b/chrome/utility/image_writer/disk_unmounter_mac.cc
@@ -89,8 +89,8 @@ void DiskUnmounterMac::DiskUnmounted(DADiskRef disk,
 }
 
 // static
-scoped_ptr<base::MessagePump> DiskUnmounterMac::CreateMessagePump() {
-  return scoped_ptr<base::MessagePump>(new base::MessagePumpCFRunLoop);
+std::unique_ptr<base::MessagePump> DiskUnmounterMac::CreateMessagePump() {
+  return std::unique_ptr<base::MessagePump>(new base::MessagePumpCFRunLoop);
 }
 
 void DiskUnmounterMac::UnmountOnWorker(const std::string& device_path) {