Replace NULL with nullptr in all C++ files.

webrtc/test/configurable_frame_size_encoder.cc

Index: webrtc/test/configurable_frame_size_encoder.cc
diff --git a/webrtc/test/configurable_frame_size_encoder.cc b/webrtc/test/configurable_frame_size_encoder.cc
index bef62405dd65211fbe935c1740e08b7ffdcab4ad..e581306be24f697384869dbae952d423b1af719f 100644
--- a/webrtc/test/configurable_frame_size_encoder.cc
+++ b/webrtc/test/configurable_frame_size_encoder.cc
@@ -22,7 +22,7 @@ namespace test {
 
 ConfigurableFrameSizeEncoder::ConfigurableFrameSizeEncoder(
     size_t max_frame_size)
-    : callback_(NULL),
+    : callback_(nullptr),
       max_frame_size_(max_frame_size),
       current_frame_size_(max_frame_size),
       buffer_(new uint8_t[max_frame_size]) {
@@ -50,7 +50,7 @@ int32_t ConfigurableFrameSizeEncoder::Encode(
   encodedImage._frameType = kVideoFrameKey;
   encodedImage._timeStamp = inputImage.timestamp();
   encodedImage.capture_time_ms_ = inputImage.render_time_ms();
-  RTPFragmentationHeader* fragmentation = NULL;
+  RTPFragmentationHeader* fragmentation = nullptr;
   CodecSpecificInfo specific;
   memset(&specific, 0, sizeof(specific));
   callback_->OnEncodedImage(encodedImage, &specific, fragmentation);