Mojo: NULL -> nullptr in mojo/system and mojo/embedder.

mojo/embedder/platform_channel_pair_posix_unittest.cc

 // 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.
 
 #include "mojo/embedder/platform_channel_pair.h"
 
 #include <errno.h>
 #include <poll.h>
 #include <signal.h>
 #include <stdio.h>
@@ skipping 35 matching lines @@
 
   virtual void SetUp() OVERRIDE {
     // Make sure |SIGPIPE| isn't being ignored.
     struct sigaction action = {};
     action.sa_handler = SIG_DFL;
     ASSERT_EQ(0, sigaction(SIGPIPE, &action, &old_action_));
   }
 
   virtual void TearDown() OVERRIDE {
     // Restore the |SIGPIPE| handler.
-    ASSERT_EQ(0, sigaction(SIGPIPE, &old_action_, NULL));
+    ASSERT_EQ(0, sigaction(SIGPIPE, &old_action_, nullptr));
   }
 
  private:
   struct sigaction old_action_;
 
   DISALLOW_COPY_AND_ASSIGN(PlatformChannelPairPosixTest);
 };
 
 TEST_F(PlatformChannelPairPosixTest, NoSigPipe) {
   PlatformChannelPair channel_pair;
@@ skipping 179 matching lines @@
     char read_buf[100];
     size_t bytes_read = fread(read_buf, 1, sizeof(read_buf), fp.get());
     EXPECT_EQ(file_contents.size(), bytes_read);
     EXPECT_EQ(file_contents, std::string(read_buf, bytes_read));
   }
 }
 
 }  // namespace
 }  // namespace embedder
 }  // namespace mojo