Replace NULL with nullptr in all C++ files.

webrtc/voice_engine/test/auto_test/standard/file_before_streaming_test.cc

Index: webrtc/voice_engine/test/auto_test/standard/file_before_streaming_test.cc
diff --git a/webrtc/voice_engine/test/auto_test/standard/file_before_streaming_test.cc b/webrtc/voice_engine/test/auto_test/standard/file_before_streaming_test.cc
index 96ac03c5307e498004606f70870e44051f49ae39..e6ba9c80b10a345fc52814f36f6696f488c8c6c3 100644
--- a/webrtc/voice_engine/test/auto_test/standard/file_before_streaming_test.cc
+++ b/webrtc/voice_engine/test/auto_test/standard/file_before_streaming_test.cc
@@ -42,7 +42,7 @@ class FileBeforeStreamingTest : public AfterInitializationFixture {
   // will be one second longer than the duration of the test.
   void GenerateInputFile() {
     FILE* input_file = fopen(input_filename_.c_str(), "wb");
-    ASSERT_TRUE(input_file != NULL);
+    ASSERT_TRUE(input_file != nullptr);
     for (int i = 0; i < kSampleRateHz / 1000 * (kTestDurationMs + 1000); i++) {
       ASSERT_EQ(1u, fwrite(&kInputValue, sizeof(kInputValue), 1, input_file));
     }
@@ -59,7 +59,7 @@ class FileBeforeStreamingTest : public AfterInitializationFixture {
 
   void VerifyOutput(int16_t target_value) {
     FILE* output_file = fopen(output_filename_.c_str(), "rb");
-    ASSERT_TRUE(output_file != NULL);
+    ASSERT_TRUE(output_file != nullptr);
     int16_t output_value = 0;
     int samples_read = 0;
 
@@ -82,7 +82,7 @@ class FileBeforeStreamingTest : public AfterInitializationFixture {
 
 void VerifyEmptyOutput() {
   FILE* output_file = fopen(output_filename_.c_str(), "rb");
-  ASSERT_TRUE(output_file != NULL);
+  ASSERT_TRUE(output_file != nullptr);
   ASSERT_EQ(0, fseek(output_file, 0, SEEK_END));
   EXPECT_EQ(0, ftell(output_file));
   ASSERT_EQ(0, fclose(output_file));