Support HLS MPEG2 TS with SAMPLE-AES encryption.

media/base/bit_reader.cc

Index: media/base/bit_reader.cc
diff --git a/media/base/bit_reader.cc b/media/base/bit_reader.cc
index c0d30d66fdd5d0deca5f446b25bd7e812cfbbd46..48ec5833b2ce8d084cf93aa8fa3d670ccbaf79d7 100644
--- a/media/base/bit_reader.cc
+++ b/media/base/bit_reader.cc
@@ -31,4 +31,15 @@ int BitReader::GetBytes(int max_nbytes, const uint8** out) {
   return nbytes;
 }
 
+bool BitReader::ReadString(int num_bits, std::string* str) {
+  int num_bytes = num_bits / 8;
+  DCHECK_EQ(num_bits % 8, 0);
+  str->resize(num_bytes);
+  char* ptr = &str->front();
+  while (num_bytes--)
+    if (!ReadBits(8, ptr++))
+      return false;
+  return true;
+}
+
 }  // namespace media