Update mojo sdk to rev 126532ce21c5c3c55a1e1693731411cb60169efd

third_party/mojo/src/mojo/public/cpp/system/buffer.h

Index: third_party/mojo/src/mojo/public/cpp/system/buffer.h
diff --git a/third_party/mojo/src/mojo/public/cpp/system/buffer.h b/third_party/mojo/src/mojo/public/cpp/system/buffer.h
index 68172973ca93a2c1355001d835c8cb3a7b3ec668..9458c0aec7bd804f7027a5c1c897f206b0a2daa4 100644
--- a/third_party/mojo/src/mojo/public/cpp/system/buffer.h
+++ b/third_party/mojo/src/mojo/public/cpp/system/buffer.h
@@ -2,6 +2,13 @@
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
+// This file provides a C++ wrapping around the Mojo C API for shared buffers,
+// replacing the prefix of "Mojo" with a "mojo" namespace, and using more
+// strongly-typed representations of |MojoHandle|s.
+//
+// Please see "mojo/public/c/system/buffer.h" for complete documentation of the
+// API.
+
 #ifndef MOJO_PUBLIC_CPP_SYSTEM_BUFFER_H_
 #define MOJO_PUBLIC_CPP_SYSTEM_BUFFER_H_
 
@@ -13,8 +20,8 @@
 
 namespace mojo {
 
-// SharedBufferHandle ----------------------------------------------------------
-
+// A strongly-typed representation of a |MojoHandle| referring to a shared
+// buffer.
 class SharedBufferHandle : public Handle {
  public:
   SharedBufferHandle() {}
@@ -30,6 +37,8 @@ typedef ScopedHandleBase<SharedBufferHandle> ScopedSharedBufferHandle;
 static_assert(sizeof(ScopedSharedBufferHandle) == sizeof(SharedBufferHandle),
               "Bad size for C++ ScopedSharedBufferHandle");
 
+// Creates a shared buffer. See |MojoCreateSharedBuffer()| for complete
+// documentation.
 inline MojoResult CreateSharedBuffer(
     const MojoCreateSharedBufferOptions* options,
     uint64_t num_bytes,
@@ -44,10 +53,17 @@ inline MojoResult CreateSharedBuffer(
   return rv;
 }
 
+// Duplicates a handle to a buffer, most commonly so that the buffer can be
+// shared with other applications. See |MojoDuplicateBufferHandle()| for
+// complete documentation.
+//
+// TODO(ggowan): Rename this to DuplicateBufferHandle since it is making another
+// handle to the same buffer, not duplicating the buffer itself.
+//
 // TODO(vtl): This (and also the functions below) are templatized to allow for
 // future/other buffer types. A bit "safer" would be to overload this function
-// manually. (The template enforces that the in and out handles to be of the
-// same type.)
+// manually. (The template enforces that the in and out handles be of the same
+// type.)
 template <class BufferHandleType>
 inline MojoResult DuplicateBuffer(
     BufferHandleType buffer,
@@ -63,6 +79,8 @@ inline MojoResult DuplicateBuffer(
   return rv;
 }
 
+// Maps a part of a buffer (specified by |buffer|, |offset|, and |num_bytes|)
+// into memory. See |MojoMapBuffer()| for complete documentation.
 template <class BufferHandleType>
 inline MojoResult MapBuffer(BufferHandleType buffer,
                             uint64_t offset,
@@ -73,6 +91,8 @@ inline MojoResult MapBuffer(BufferHandleType buffer,
   return MojoMapBuffer(buffer.value(), offset, num_bytes, pointer, flags);
 }
 
+// Unmaps a part of a buffer that was previously mapped with |MapBuffer()|.
+// See |MojoUnmapBuffer()| for complete documentation.
 inline MojoResult UnmapBuffer(void* pointer) {
   assert(pointer);
   return MojoUnmapBuffer(pointer);