Remove checksum in CDM interface and implementations.

webkit/media/crypto/ppapi/clear_key_cdm.cc

Index: webkit/media/crypto/ppapi/clear_key_cdm.cc
diff --git a/webkit/media/crypto/ppapi/clear_key_cdm.cc b/webkit/media/crypto/ppapi/clear_key_cdm.cc
index 94addb4d73bde1a4789b51767f3613e3376793bc..ef292535389b268a0bc4965b93c800067d77aa53 100644
--- a/webkit/media/crypto/ppapi/clear_key_cdm.cc
+++ b/webkit/media/crypto/ppapi/clear_key_cdm.cc
@@ -26,13 +26,13 @@ static scoped_refptr<media::DecoderBuffer> CopyDecoderBufferFrom(
     subsamples.push_back(subsample);
   }
 
+  // TODO(xhwang): Update this code when checksum is removed in DecryptConfig.
   scoped_ptr<media::DecryptConfig> decrypt_config(new media::DecryptConfig(
       std::string(reinterpret_cast<const char*>(input_buffer.key_id),
                   input_buffer.key_id_size),
       std::string(reinterpret_cast<const char*>(input_buffer.iv),
                   input_buffer.iv_size),
-      std::string(reinterpret_cast<const char*>(input_buffer.checksum),
-                  input_buffer.checksum_size),
+      std::string(),
       input_buffer.data_offset,
       subsamples));