Remove unused methods

[ Merge of http://go/wvgerrit/16405/ ]

Methods in string conversion and license request tests were not being used.
This was detected by static analysis cppcheck reports.

b/26349052

Change-Id: I44779abf6b6fdc01b5391bff7d47be1d20ef84d2

libwvdrmengine/cdm/core/test/license_request.cpp

@@ -55,30 +55,4 @@ void LicenseRequest::GetDrmMessage(const std::string& response,
   }
 }
 
-// Returns heartbeat url in heartbeat_url.
-// The heartbeat url is stored as meta data in the response message.
-void LicenseRequest::GetHeartbeatUrl(const std::string& response,
-                                     std::string& heartbeat_url) {
-  if (response.empty()) {
-    heartbeat_url.clear();
-    return;
-  }
-
-  size_t header_end_pos = FindHeaderEndPosition(response);
-  if (header_end_pos != std::string::npos) {
-    header_end_pos += kTwoBlankLines.size();  // points to response body
-
-    heartbeat_url.clear();
-    size_t heartbeat_url_pos = response.find("Heartbeat-Url: ", header_end_pos);
-    if (heartbeat_url_pos != std::string::npos) {
-      heartbeat_url_pos += sizeof("Heartbeat-Url: ");
-      heartbeat_url.assign(response.substr(heartbeat_url_pos));
-    } else {
-      LOGE("heartbeat url not found");
-    }
-  } else {
-    LOGE("response body not found");
-  }
-}
-
 }  // namespace wvcdm