Replace NULL with nullptr in all C++ files.

webrtc/modules/audio_processing/echo_control_mobile_impl.cc

Index: webrtc/modules/audio_processing/echo_control_mobile_impl.cc
diff --git a/webrtc/modules/audio_processing/echo_control_mobile_impl.cc b/webrtc/modules/audio_processing/echo_control_mobile_impl.cc
index a9457d96d9de21ab1712d080f530e7d3e88b0326..a00927dbb8bd01124dfcca9a47fbece0fb1b14db 100644
--- a/webrtc/modules/audio_processing/echo_control_mobile_impl.cc
+++ b/webrtc/modules/audio_processing/echo_control_mobile_impl.cc
@@ -96,7 +96,7 @@ class EchoControlMobileImpl::Canceller {
     RTC_DCHECK(state_);
     int error = WebRtcAecm_Init(state_, sample_rate_hz);
     RTC_DCHECK_EQ(AudioProcessing::kNoError, error);
-    if (external_echo_path != NULL) {
+    if (external_echo_path != nullptr) {
       error = WebRtcAecm_InitEchoPath(state_, external_echo_path,
                                       echo_path_size_bytes);
       RTC_DCHECK_EQ(AudioProcessing::kNoError, error);
@@ -114,15 +114,15 @@ EchoControlMobileImpl::EchoControlMobileImpl(rtc::CriticalSection* crit_render,
       crit_capture_(crit_capture),
       routing_mode_(kSpeakerphone),
       comfort_noise_enabled_(true),
-      external_echo_path_(NULL) {
+      external_echo_path_(nullptr) {
   RTC_DCHECK(crit_render);
   RTC_DCHECK(crit_capture);
 }
 
 EchoControlMobileImpl::~EchoControlMobileImpl() {
-    if (external_echo_path_ != NULL) {
-      delete [] external_echo_path_;
-      external_echo_path_ = NULL;
+  if (external_echo_path_ != nullptr) {
+    delete[] external_echo_path_;
+    external_echo_path_ = nullptr;
     }
 }
 
@@ -201,9 +201,9 @@ int EchoControlMobileImpl::ProcessCaptureAudio(AudioBuffer* audio,
     //            This is kind of hacked up.
     const int16_t* noisy = audio->low_pass_reference(capture);
     const int16_t* clean = audio->split_bands_const(capture)[kBand0To8kHz];
-    if (noisy == NULL) {
+    if (noisy == nullptr) {
       noisy = clean;
-      clean = NULL;
+      clean = nullptr;
     }
     for (size_t render = 0; render < stream_properties_->num_reverse_channels;
          ++render) {
@@ -293,7 +293,7 @@ int EchoControlMobileImpl::SetEchoPath(const void* echo_path,
   {
     rtc::CritScope cs_render(crit_render_);
     rtc::CritScope cs_capture(crit_capture_);
-    if (echo_path == NULL) {
+    if (echo_path == nullptr) {
       return AudioProcessing::kNullPointerError;
     }
     if (size_bytes != echo_path_size_bytes()) {
@@ -301,7 +301,7 @@ int EchoControlMobileImpl::SetEchoPath(const void* echo_path,
       return AudioProcessing::kBadParameterError;
     }
 
-    if (external_echo_path_ == NULL) {
+    if (external_echo_path_ == nullptr) {
       external_echo_path_ = new unsigned char[size_bytes];
     }
     memcpy(external_echo_path_, echo_path, size_bytes);
@@ -319,7 +319,7 @@ int EchoControlMobileImpl::SetEchoPath(const void* echo_path,
 int EchoControlMobileImpl::GetEchoPath(void* echo_path,
                                        size_t size_bytes) const {
   rtc::CritScope cs(crit_capture_);
-  if (echo_path == NULL) {
+  if (echo_path == nullptr) {
     return AudioProcessing::kNullPointerError;
   }
   if (size_bytes != echo_path_size_bytes()) {