diff --git a/media/filters/decrypting_audio_decoder.cc b/media/filters/decrypting_audio_decoder.cc
index 2c8020d908d2a..ed41d539c67fb 100644
--- a/media/filters/decrypting_audio_decoder.cc
+++ b/media/filters/decrypting_audio_decoder.cc
@@ -37,13 +37,7 @@ static inline bool IsOutOfSync(const base::TimeDelta& timestamp_1,
 DecryptingAudioDecoder::DecryptingAudioDecoder(
     const scoped_refptr<base::SingleThreadTaskRunner>& task_runner,
     MediaLog* media_log)
-    : task_runner_(task_runner),
-      media_log_(media_log),
-      state_(kUninitialized),
-      decryptor_(NULL),
-      key_added_while_decode_pending_(false),
-      support_clear_content_(false),
-      weak_factory_(this) {}
+    : task_runner_(task_runner), media_log_(media_log), weak_factory_(this) {}
 
 std::string DecryptingAudioDecoder::GetDisplayName() const {
   return "DecryptingAudioDecoder";
diff --git a/media/filters/decrypting_audio_decoder.h b/media/filters/decrypting_audio_decoder.h
index abc1d089b82e3..95f8d23429567 100644
--- a/media/filters/decrypting_audio_decoder.h
+++ b/media/filters/decrypting_audio_decoder.h
@@ -88,11 +88,11 @@ class MEDIA_EXPORT DecryptingAudioDecoder : public AudioDecoder {
   // Sets timestamps for |frames| and then passes them to |output_cb_|.
   void ProcessDecodedFrames(const Decryptor::AudioFrames& frames);
 
-  scoped_refptr<base::SingleThreadTaskRunner> task_runner_;
+  // Set in constructor.
+  scoped_refptr<base::SingleThreadTaskRunner> const task_runner_;
+  MediaLog* const media_log_;
 
-  MediaLog* media_log_;
-
-  State state_;
+  State state_ = kUninitialized;
 
   InitCB init_cb_;
   OutputCB output_cb_;
@@ -103,7 +103,7 @@ class MEDIA_EXPORT DecryptingAudioDecoder : public AudioDecoder {
   // The current decoder configuration.
   AudioDecoderConfig config_;
 
-  Decryptor* decryptor_;
+  Decryptor* decryptor_ = nullptr;
 
   // The buffer that needs decrypting/decoding.
   scoped_refptr<media::DecoderBuffer> pending_buffer_to_decode_;
@@ -113,13 +113,13 @@ class MEDIA_EXPORT DecryptingAudioDecoder : public AudioDecoder {
   // If this variable is true and kNoKey is returned then we need to try
   // decrypting/decoding again in case the newly added key is the correct
   // decryption key.
-  bool key_added_while_decode_pending_;
+  bool key_added_while_decode_pending_ = false;
 
   std::unique_ptr<AudioTimestampHelper> timestamp_helper_;
 
   // Once Initialized() with encrypted content support, if the stream changes to
   // clear content, we want to ensure this decoder remains used.
-  bool support_clear_content_;
+  bool support_clear_content_ = false;
 
   base::WeakPtr<DecryptingAudioDecoder> weak_this_;
   base::WeakPtrFactory<DecryptingAudioDecoder> weak_factory_;
diff --git a/media/filters/decrypting_video_decoder.cc b/media/filters/decrypting_video_decoder.cc
index 32ed82c2eab83..1c0a3a975cf26 100644
--- a/media/filters/decrypting_video_decoder.cc
+++ b/media/filters/decrypting_video_decoder.cc
@@ -24,13 +24,7 @@ const char DecryptingVideoDecoder::kDecoderName[] = "DecryptingVideoDecoder";
 DecryptingVideoDecoder::DecryptingVideoDecoder(
     const scoped_refptr<base::SingleThreadTaskRunner>& task_runner,
     MediaLog* media_log)
-    : task_runner_(task_runner),
-      media_log_(media_log),
-      state_(kUninitialized),
-      decryptor_(NULL),
-      key_added_while_decode_pending_(false),
-      support_clear_content_(false),
-      weak_factory_(this) {}
+    : task_runner_(task_runner), media_log_(media_log), weak_factory_(this) {}
 
 std::string DecryptingVideoDecoder::GetDisplayName() const {
   return kDecoderName;
diff --git a/media/filters/decrypting_video_decoder.h b/media/filters/decrypting_video_decoder.h
index a9229c97b6b87..03cec55319598 100644
--- a/media/filters/decrypting_video_decoder.h
+++ b/media/filters/decrypting_video_decoder.h
@@ -84,11 +84,11 @@ class MEDIA_EXPORT DecryptingVideoDecoder : public VideoDecoder {
   void CompletePendingDecode(Decryptor::Status status);
   void CompleteWaitingForDecryptionKey();
 
-  scoped_refptr<base::SingleThreadTaskRunner> task_runner_;
+  // Set in constructor.
+  scoped_refptr<base::SingleThreadTaskRunner> const task_runner_;
+  MediaLog* const media_log_;
 
-  MediaLog* media_log_;
-
-  State state_;
+  State state_ = kUninitialized;
 
   InitCB init_cb_;
   OutputCB output_cb_;
@@ -98,7 +98,7 @@ class MEDIA_EXPORT DecryptingVideoDecoder : public VideoDecoder {
 
   VideoDecoderConfig config_;
 
-  Decryptor* decryptor_;
+  Decryptor* decryptor_ = nullptr;
 
   // The buffer that needs decrypting/decoding.
   scoped_refptr<media::DecoderBuffer> pending_buffer_to_decode_;
@@ -108,11 +108,11 @@ class MEDIA_EXPORT DecryptingVideoDecoder : public VideoDecoder {
   // If this variable is true and kNoKey is returned then we need to try
   // decrypting/decoding again in case the newly added key is the correct
   // decryption key.
-  bool key_added_while_decode_pending_;
+  bool key_added_while_decode_pending_ = false;
 
   // Once Initialized() with encrypted content support, if the stream changes to
   // clear content, we want to ensure this decoder remains used.
-  bool support_clear_content_;
+  bool support_clear_content_ = false;
 
   base::WeakPtr<DecryptingVideoDecoder> weak_this_;
   base::WeakPtrFactory<DecryptingVideoDecoder> weak_factory_;