C++11 declares a type safe null pointer

content/common/gpu/media/h264_dpb.cc

Index: content/common/gpu/media/h264_dpb.cc
diff --git a/content/common/gpu/media/h264_dpb.cc b/content/common/gpu/media/h264_dpb.cc
index 371d61283139a4df1084b653d6e645ae9edd8a8e..d248deec8ef65a71c217a8727f79a6862c7233b1 100644
--- a/content/common/gpu/media/h264_dpb.cc
+++ b/content/common/gpu/media/h264_dpb.cc
@@ -72,7 +72,7 @@ H264Picture* H264DPB::GetShortRefPicByPicNum(int pic_num) {
   }
 
   DVLOG(1) << "Missing short ref pic num: " << pic_num;
-  return NULL;
+  return nullptr;
 }
 
 H264Picture* H264DPB::GetLongRefPicByLongTermPicNum(int pic_num) {
@@ -83,11 +83,11 @@ H264Picture* H264DPB::GetLongRefPicByLongTermPicNum(int pic_num) {
   }
 
   DVLOG(1) << "Missing long term pic num: " << pic_num;
-  return NULL;
+  return nullptr;
 }
 
 H264Picture* H264DPB::GetLowestFrameNumWrapShortRefPic() {
-  H264Picture* ret = NULL;
+  H264Picture* ret = nullptr;
   for (size_t i = 0; i < pics_.size(); ++i) {
     H264Picture* pic = pics_[i];
     if (pic->ref && !pic->long_term &&