Convert remaining scoped_ptr -> std::unique_ptr in //mojo/edk (minus js).

mojo/edk/system/raw_channel_posix.cc

Index: mojo/edk/system/raw_channel_posix.cc
diff --git a/mojo/edk/system/raw_channel_posix.cc b/mojo/edk/system/raw_channel_posix.cc
index a7fa16e7db68492031a800aed15da3f0c240a41a..d740516e7d52628dd21698c4c6f817ff8eb67175 100644
--- a/mojo/edk/system/raw_channel_posix.cc
+++ b/mojo/edk/system/raw_channel_posix.cc
@@ -143,7 +143,7 @@ void RawChannelPosix::EnqueueMessageNoLock(
                 platform_handles->begin() + i +
                     embedder::kPlatformChannelMaxNumHandles));
         fd_message->SetTransportData(util::MakeUnique<TransportData>(
-            fds.Pass(), GetSerializedPlatformHandleSize()));
+            std::move(fds), GetSerializedPlatformHandleSize()));
         RawChannel::EnqueueMessageNoLock(std::move(fd_message));
       }
 
@@ -209,7 +209,7 @@ embedder::ScopedPlatformHandleVectorPtr RawChannelPosix::GetReadPlatformHandles(
   read_platform_handles_.erase(
       read_platform_handles_.begin(),
       read_platform_handles_.begin() + num_platform_handles);
-  return rv.Pass();
+  return rv;
 }
 
 RawChannel::IOResult RawChannelPosix::WriteNoLock(