ChannelMojo: Handle errors in pending message processing.

ipc/mojo/ipc_message_pipe_reader.h

Index: ipc/mojo/ipc_message_pipe_reader.h
diff --git a/ipc/mojo/ipc_message_pipe_reader.h b/ipc/mojo/ipc_message_pipe_reader.h
index ecfa018b5e02ba8712df8c17259f77c1c1f9355b..bd82883bd88400802adeff60e1d47199d2282ee6 100644
--- a/ipc/mojo/ipc_message_pipe_reader.h
+++ b/ipc/mojo/ipc_message_pipe_reader.h
@@ -8,6 +8,7 @@
 #include <vector>
 
 #include "base/memory/scoped_ptr.h"
+#include "ipc/ipc_export.h"
 #include "mojo/public/c/environment/async_waiter.h"
 #include "mojo/public/cpp/system/core.h"
 
@@ -28,7 +29,7 @@ namespace internal {
 //
 // MessageReader has to be used in IO thread. It isn't thread-safe.
 //
-class MessagePipeReader {
+class IPC_MOJO_EXPORT MessagePipeReader {
  public:
   // Delay the object deletion using the current message loop.
   // This is intended to used by MessagePipeReader owners.