Mojo: Dispatcher::MessageInTransitAccess functions don't need to take the lock.

mojo/system/message_in_transit.h

 // Copyright 2013 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.
 
 #ifndef MOJO_SYSTEM_MESSAGE_IN_TRANSIT_H_
 #define MOJO_SYSTEM_MESSAGE_IN_TRANSIT_H_
 
 #include <stdint.h>
 
 #include <vector>
@@ skipping 249 matching lines @@
     uint32_t offset;  // Relative to the start of the secondary buffer.
     uint32_t size;  // (Not including any padding.)
     uint32_t unused;
   };
 
   // The maximum possible size of a valid secondary buffer: for each handle,
   // there'll be a handle table entry and its serialized data.
   static const size_t kMaxSecondaryBufferSize;
 
   // Validates the secondary buffer. Returns null on success, or a
-  // human-readable error message on error.
+  // human-readable error message (meant for logging/debugging) on error.
   static const char* ValidateSecondaryBuffer(size_t num_handles,
                                              const void* secondary_buffer,
                                              size_t secondary_buffer_size);
 
   const Header* header() const {
     return static_cast<const Header*>(main_buffer_);
   }
   Header* header() { return static_cast<Header*>(main_buffer_); }
 
   void UpdateTotalSize();
@@ skipping 16 matching lines @@
   // TODO(vtl): With C++11, change it to a vector of |ScopedPlatformHandles|.
   scoped_ptr<std::vector<embedder::PlatformHandle> > platform_handles_;
 
   DISALLOW_COPY_AND_ASSIGN(MessageInTransit);
 };
 
 }  // namespace system
 }  // namespace mojo
 
 #endif  // MOJO_SYSTEM_MESSAGE_IN_TRANSIT_H_