Minor tweaks to API documentation and code comments.

mojo/public/c/system/buffer.h

 // Copyright 2014 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.
 
 // This file contains types/constants and functions specific to buffers (and in
 // particular shared buffers).
 // TODO(vtl): Reorganize this file (etc.) to separate general buffer functions
 // from (shared) buffer creation.
 //
 // Note: This header should be compilable as C.
@@ skipping 151 matching lines @@
 //       |offset| and |num_bytes| is not valid).
 //   |MOJO_RESULT_RESOURCE_EXHAUSTED| if the mapping operation itself failed
 //       (e.g., due to not having appropriate address space available).
 MOJO_SYSTEM_EXPORT MojoResult MojoMapBuffer(MojoHandle buffer_handle,
                                             uint64_t offset,
                                             uint64_t num_bytes,
                                             void** buffer,  // Out.
                                             MojoMapBufferFlags flags);
 
 // Unmaps a buffer pointer that was mapped by |MojoMapBuffer()|. |buffer| must
-// have been the result of |MojoMapBuffer()| (not some pointer strictly inside
+// have been the result of |MojoMapBuffer()| (not some other pointer inside
 // the mapped memory), and the entire mapping will be removed (partial unmapping
-// is not supported). A mapping may only be unmapped exactly once.
+// is not supported). A mapping may only be unmapped once.
 //
 // Returns:
 //   |MOJO_RESULT_OK| on success.
 //   |MOJO_RESULT_INVALID_ARGUMENT| if |buffer| is invalid (e.g., is not the
 //       result of |MojoMapBuffer()| or has already been unmapped).
 MOJO_SYSTEM_EXPORT MojoResult MojoUnmapBuffer(void* buffer);  // In.
 
 #ifdef __cplusplus
 }  // extern "C"
 #endif
 
 #endif  // MOJO_PUBLIC_C_SYSTEM_BUFFER_H_