Fix media_cas_proxy_sdk build issue.

Add example binary for testing building the SDK after 'git clone' from our repo.

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Created by MOE: https://github.com/google/moe
MOE_MIGRATED_REVID=227583629

common/test_utils.h

@@ -14,7 +14,7 @@
 
 #include <string>
 
-#include "util/status.h"
+#include "common/status.h"
 
 namespace widevine {
 
@@ -23,9 +23,9 @@ namespace widevine {
 // |message| is the message to be signed, and |signature| is a pointer to a
 // std::string where the signature will be stored. The caller returns ownership of
 // all paramters.
-util::Status GenerateRsaSignatureSha256Pkcs1(const std::string& pem_private_key,
-                                             const std::string& message,
-                                             std::string* signature);
+Status GenerateRsaSignatureSha256Pkcs1(const std::string& pem_private_key,
+                                       const std::string& message,
+                                       std::string* signature);
 
 }  // namespace widevine