Bug 1759846 - the 'empty' method should be used to check for emptines…

…s. r=sylvestre

In ClearKeyUtils.cpp: the 'empty' method should be used to check
for emptiness instead of 'size'

Differential Revision: https://phabricator.services.mozilla.com/D141956

media/gmp-clearkey/0.1/ClearKeyUtils.cpp

@@ -262,7 +262,7 @@ static bool EncodeBase64Web(vector<uint8_t> aBinary, string& aEncoded) {
 void ClearKeyUtils::MakeKeyRequest(const vector<KeyId>& aKeyIDs,
                                    string& aOutRequest,
                                    SessionType aSessionType) {
-  assert(aKeyIDs.size() && aOutRequest.empty());
+  assert(!aKeyIDs.empty() && aOutRequest.empty());
 
   aOutRequest.append("{\"kids\":[");
   for (size_t i = 0; i < aKeyIDs.size(); i++) {