Add a clarifying comment to the memory layout navigation. (Inspired by Coverity CID 100022)

R=tommi@chromium.org
BUG=None
TEST=None


Review URL: https://chromiumcodereview.appspot.com/10826014

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@148412 0039d316-1c4b-4281-b951-d872f2087c98

courgette/memory_allocator.cc

-// Copyright (c) 2011 The Chromium Authors. All rights reserved.
+// Copyright (c) 2012 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.
 
@@ -135,6 +135,8 @@ bool TempMapping::Initialize(size_t size) {
 
 void* TempMapping::memory() const {
   uint8* mem = reinterpret_cast<uint8*>(mapping_.view());
+  // The 'this' pointer is written at the start of mapping_.view(), so
+  // go past it. (See Initialize()).
   if (mem)
     mem += sizeof(this);
   DCHECK(mem);