diff --git a/media/base/media_sample.cc b/media/base/media_sample.cc
index 9448ddae9b..74e0cb023e 100644
--- a/media/base/media_sample.cc
+++ b/media/base/media_sample.cc
@@ -7,18 +7,19 @@
 #include "media/base/media_sample.h"
 
 #include "base/logging.h"
+#include "base/strings/stringprintf.h"
 #include "media/base/decrypt_config.h"
 
 namespace media {
 
 MediaSample::MediaSample(const uint8* data,
-                         int size,
+                         size_t size,
                          const uint8* side_data,
-                         int side_data_size,
+                         size_t side_data_size,
                          bool is_key_frame)
     : dts_(0), pts_(0), duration_(0), is_key_frame_(is_key_frame) {
   if (!data) {
-    CHECK_EQ(size, 0);
+    CHECK_EQ(size, 0u);
     CHECK(!side_data);
     return;
   }
@@ -32,19 +33,19 @@ MediaSample::~MediaSample() {}
 
 // static
 scoped_refptr<MediaSample> MediaSample::CopyFrom(const uint8* data,
-                                                 int data_size,
+                                                 size_t data_size,
                                                  bool is_key_frame) {
   // If you hit this CHECK you likely have a bug in a demuxer. Go fix it.
   CHECK(data);
   return make_scoped_refptr(
-      new MediaSample(data, data_size, NULL, 0, is_key_frame));
+      new MediaSample(data, data_size, NULL, 0u, is_key_frame));
 }
 
 // static
 scoped_refptr<MediaSample> MediaSample::CopyFrom(const uint8* data,
-                                                 int data_size,
+                                                 size_t data_size,
                                                  const uint8* side_data,
-                                                 int side_data_size,
+                                                 size_t side_data_size,
                                                  bool is_key_frame) {
   // If you hit this CHECK you likely have a bug in a demuxer. Go fix it.
   CHECK(data);
@@ -58,19 +59,13 @@ scoped_refptr<MediaSample> MediaSample::CreateEOSBuffer() {
 }
 
 std::string MediaSample::ToString() const {
-  if (end_of_stream()) {
-    return "end of stream";
-  }
-
-  std::ostringstream s;
-  s << "dts: " << dts_
-    << " pts: " << pts_
-    << " duration: " << duration_
-    << " is_key_frame: " << is_key_frame_
-    << " size: " << data_.size()
-    << " side_data_size: " << side_data_.size()
-    << " encrypted: " << (decrypt_config_ != NULL);
-  return s.str();
+  if (end_of_stream())
+    return "End of stream sample\n";
+  return base::StringPrintf(
+      "dts: %ld\n pts: %ld\n duration: %ld\n is_key_frame: %s\n size: %zu\n "
+      "side_data_size: %zu\n is_encrypted: %s\n",
+      dts_, pts_, duration_, is_key_frame_ ? "true" : "false", data_.size(),
+      side_data_.size(), decrypt_config_ ? "true" : "false");
 }
 
 }  // namespace media
diff --git a/media/base/media_sample.h b/media/base/media_sample.h
index e17b011153..4047f2702d 100644
--- a/media/base/media_sample.h
+++ b/media/base/media_sample.h
@@ -29,7 +29,7 @@ class MediaSample : public base::RefCountedThreadSafe<MediaSample> {
   /// @param size indicates sample size in bytes. Must not be negative.
   /// @param is_key_frame indicates whether the sample is a key frame.
   static scoped_refptr<MediaSample> CopyFrom(const uint8* data,
-                                             int size,
+                                             size_t size,
                                              bool is_key_frame);
 
   /// Create a MediaSample object from input.
@@ -43,9 +43,9 @@ class MediaSample : public base::RefCountedThreadSafe<MediaSample> {
   ///        Must not be negative.
   /// @param is_key_frame indicates whether the sample is a key frame.
   static scoped_refptr<MediaSample> CopyFrom(const uint8* data,
-                                             int size,
+                                             size_t size,
                                              const uint8* side_data,
-                                             int side_data_size,
+                                             size_t side_data_size,
                                              bool is_key_frame);
 
   /// Create a MediaSample indicating we've reached end of stream.
@@ -98,7 +98,7 @@ class MediaSample : public base::RefCountedThreadSafe<MediaSample> {
     return &data_[0];
   }
 
-  int data_size() const {
+  size_t data_size() const {
     DCHECK(!end_of_stream());
     return data_.size();
   }
@@ -108,7 +108,7 @@ class MediaSample : public base::RefCountedThreadSafe<MediaSample> {
     return &side_data_[0];
   }
 
-  int side_data_size() const {
+  size_t side_data_size() const {
     DCHECK(!end_of_stream());
     return side_data_.size();
   }
@@ -136,9 +136,9 @@ class MediaSample : public base::RefCountedThreadSafe<MediaSample> {
   /// @param data,side_data can be NULL, which indicates an empty sample.
   /// @param size,side_data_size should not be negative.
   MediaSample(const uint8* data,
-              int size,
+              size_t size,
               const uint8* side_data,
-              int side_data_size,
+              size_t side_data_size,
               bool is_key_frame);
   virtual ~MediaSample();
 
diff --git a/media/base/media_stream.cc b/media/base/media_stream.cc
index c9d2f6c5f1..5a1e2380dd 100644
--- a/media/base/media_stream.cc
+++ b/media/base/media_stream.cc
@@ -7,6 +7,7 @@
 #include "media/base/media_stream.h"
 
 #include "base/logging.h"
+#include "base/strings/stringprintf.h"
 #include "media/base/demuxer.h"
 #include "media/base/media_sample.h"
 #include "media/base/muxer.h"
@@ -51,14 +52,14 @@ Status MediaStream::PushSample(const scoped_refptr<MediaSample>& sample) {
 }
 
 void MediaStream::Connect(Muxer* muxer) {
-  DCHECK(muxer != NULL);
-  DCHECK(muxer_ == NULL);
+  DCHECK(muxer);
+  DCHECK(!muxer_);
   state_ = kConnected;
   muxer_ = muxer;
 }
 
 Status MediaStream::Start(MediaStreamOperation operation) {
-  DCHECK(demuxer_ != NULL);
+  DCHECK(demuxer_);
   DCHECK(operation == kPush || operation == kPull);
 
   switch (state_) {
@@ -99,10 +100,8 @@ Status MediaStream::Start(MediaStreamOperation operation) {
 const scoped_refptr<StreamInfo> MediaStream::info() const { return info_; }
 
 std::string MediaStream::ToString() const {
-  std::ostringstream s;
-  s << "state: " << state_ << " samples in the queue: " << samples_.size()
-    << " " << info_->ToString();
-  return s.str();
+  return base::StringPrintf("state: %d\n samples in the queue: %zu\n %s",
+                            state_, samples_.size(), info_->ToString().c_str());
 }
 
 }  // namespace media