Replace NULL with nullptr in all C++ files.

webrtc/modules/audio_device/linux/latebindingsymboltable_linux.cc

 /*
  *  Copyright (c) 2010 The WebRTC project authors. All Rights Reserved.
  *
  *  Use of this source code is governed by a BSD-style license
  *  that can be found in the LICENSE file in the root of the source
  *  tree. An additional intellectual property rights grant can be found
  *  in the file PATENTS.  All contributing project authors may
  *  be found in the AUTHORS file in the root of the source tree.
  */
 
@@ skipping 58 matching lines @@
                        const char *symbol_name,
                        void **symbol) {
 #ifdef WEBRTC_LINUX
   *symbol = dlsym(handle, symbol_name);
   char *err = dlerror();
   if (err) {
     WEBRTC_TRACE(kTraceError, kTraceAudioDevice, -1,
                "Error loading symbol %s : %d", symbol_name, err);
     return false;
   } else if (!*symbol) {
-    WEBRTC_TRACE(kTraceError, kTraceAudioDevice, -1,
-               "Symbol %s is NULL", symbol_name);
+    WEBRTC_TRACE(kTraceError, kTraceAudioDevice, -1, "Symbol %s is null",
+                 symbol_name);
     return false;
   }
   return true;
 #else
 #error Not implemented
 #endif
 }
 
 // This routine MUST assign SOME value for every symbol, even if that value is
-// NULL, or else some symbols may be left with uninitialized data that the
+// null, or else some symbols may be left with uninitialized data that the
 // caller may later interpret as a valid address.
 bool InternalLoadSymbols(DllHandle handle,
                          int num_symbols,
                          const char *const symbol_names[],
                          void *symbols[]) {
 #ifdef WEBRTC_LINUX
   // Clear any old errors.
   dlerror();
 #endif
   for (int i = 0; i < num_symbols; ++i) {
     if (!LoadSymbol(handle, symbol_names[i], &symbols[i])) {
       return false;
     }
   }
   return true;
 }
 
 }  // namespace webrtc_adm_linux