Replace NULL with nullptr in all C++ files.

webrtc/system_wrappers/source/aligned_malloc.cc

 /*
  *  Copyright (c) 2011 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 23 matching lines @@
 // Alignment must be an integer power of two.
 bool ValidAlignment(size_t alignment) {
   if (!alignment) {
     return false;
   }
   return (alignment & (alignment - 1)) == 0;
 }
 
 void* GetRightAlign(const void* pointer, size_t alignment) {
   if (!pointer) {
-    return NULL;
+    return nullptr;
   }
   if (!ValidAlignment(alignment)) {
-    return NULL;
+    return nullptr;
   }
   uintptr_t start_pos = reinterpret_cast<uintptr_t>(pointer);
   return reinterpret_cast<void*>(GetRightAlign(start_pos, alignment));
 }
 
 void* AlignedMalloc(size_t size, size_t alignment) {
   if (size == 0) {
-    return NULL;
+    return nullptr;
   }
   if (!ValidAlignment(alignment)) {
-    return NULL;
+    return nullptr;
   }
 
   // The memory is aligned towards the lowest address that so only
   // alignment - 1 bytes needs to be allocated.
   // A pointer to the start of the memory must be stored so that it can be
   // retreived for deletion, ergo the sizeof(uintptr_t).
   void* memory_pointer = malloc(size + sizeof(uintptr_t) + alignment - 1);
-  if (memory_pointer == NULL) {
-    return NULL;
+  if (memory_pointer == nullptr) {
+    return nullptr;
   }
 
   // Aligning after the sizeof(uintptr_t) bytes will leave room for the header
   // in the same memory block.
   uintptr_t align_start_pos = reinterpret_cast<uintptr_t>(memory_pointer);
   align_start_pos += sizeof(uintptr_t);
   uintptr_t aligned_pos = GetRightAlign(align_start_pos, alignment);
   void* aligned_pointer = reinterpret_cast<void*>(aligned_pos);
 
   // Store the address to the beginning of the memory just before the aligned
   // memory.
   uintptr_t header_pos = aligned_pos - sizeof(uintptr_t);
   void* header_pointer = reinterpret_cast<void*>(header_pos);
   uintptr_t memory_start = reinterpret_cast<uintptr_t>(memory_pointer);
   memcpy(header_pointer, &memory_start, sizeof(uintptr_t));
 
   return aligned_pointer;
 }
 
 void AlignedFree(void* mem_block) {
-  if (mem_block == NULL) {
+  if (mem_block == nullptr) {
     return;
   }
   uintptr_t aligned_pos = reinterpret_cast<uintptr_t>(mem_block);
   uintptr_t header_pos = aligned_pos - sizeof(uintptr_t);
 
   // Read out the address of the AlignedMemory struct from the header.
   uintptr_t memory_start_pos = *reinterpret_cast<uintptr_t*>(header_pos);
   void* memory_start = reinterpret_cast<void*>(memory_start_pos);
   free(memory_start);
 }
 
 }  // namespace webrtc