Add audible support to the copresence API.

components/copresence/rpc/http_post.cc

Index: components/copresence/rpc/http_post.cc
diff --git a/components/copresence/rpc/http_post.cc b/components/copresence/rpc/http_post.cc
index 963f1921f7b66a84fac30c5e765285764906219d..02ccdd53deb32309b7e98c64b86b060923379acd 100644
--- a/components/copresence/rpc/http_post.cc
+++ b/components/copresence/rpc/http_post.cc
@@ -29,9 +29,7 @@ const char kApiKeyField[] = "key";
 HttpPost::HttpPost(net::URLRequestContextGetter* url_context_getter,
                    const std::string& server_host,
                    const std::string& rpc_name,
-                   const google::protobuf::MessageLite& request_proto,
-                   const ResponseCallback& response_callback)
-                   : response_callback_(response_callback) {
+                   const google::protobuf::MessageLite& request_proto) {
   // Create the base URL to call.
   GURL url(server_host + "/" + rpc_name);
 
@@ -65,6 +63,10 @@ HttpPost::HttpPost(net::URLRequestContextGetter* url_context_getter,
                              net::LOAD_DO_NOT_SEND_COOKIES |
                              net::LOAD_DO_NOT_SEND_AUTH_DATA);
   url_fetcher_->SetUploadData("application/x-protobuf", request_data);
+}
+
+void HttpPost::Start(const ResponseCallback& response_callback) {
+  response_callback_ = response_callback;
   url_fetcher_->Start();
 }
 
@@ -88,7 +90,7 @@ void HttpPost::OnURLFetchComplete(const net::URLFetcher* source) {
   }
 
   // Return the response.
-  response_callback_.Run(response_code, response, this);
+  response_callback_.Run(response_code, response);
 }
 
 }  // namespace copresence