Replace size_t with int in a few media classes.

media/base/data_buffer_unittest.cc

Index: media/base/data_buffer_unittest.cc
diff --git a/media/base/data_buffer_unittest.cc b/media/base/data_buffer_unittest.cc
index f22e05e44e812ccacb766560e8ee9e0bf8f3c9dc..27b5968ceaea5b3bb5cc350e9be927ed8e0c8891 100644
--- a/media/base/data_buffer_unittest.cc
+++ b/media/base/data_buffer_unittest.cc
@@ -30,21 +30,21 @@ TEST(DataBufferTest, StreamSampleImpl) {
 }
 
 TEST(DataBufferTest, Constructors) {
-  const size_t kTestSize = 10;
+  const int kTestSize = 10;
 
   scoped_refptr<DataBuffer> buffer(new DataBuffer(0));
   EXPECT_FALSE(buffer->GetData());
 
   scoped_refptr<DataBuffer> buffer2(new DataBuffer(kTestSize));
-  EXPECT_EQ(0u, buffer2->GetDataSize());
+  EXPECT_EQ(0, buffer2->GetDataSize());
   EXPECT_EQ(kTestSize, buffer2->GetBufferSize());
 }
 
 TEST(DataBufferTest, ReadingWriting) {
   const char kData[] = "hello";
-  const size_t kDataSize = arraysize(kData);
+  const int kDataSize = arraysize(kData);
   const char kNewData[] = "chromium";
-  const size_t kNewDataSize = arraysize(kNewData);
+  const int kNewDataSize = arraysize(kNewData);
 
   // Create a DataBuffer.
   scoped_refptr<DataBuffer> buffer(new DataBuffer(kDataSize));