Fixing HttpPost deletion crash

BUG=403284

Review URL: https://codereview.chromium.org/468213002

Cr-Commit-Position: refs/heads/master@{#289450}
git-svn-id: svn://svn.chromium.org/chrome/trunk/src@289450 0039d316-1c4b-4281-b951-d872f2087c98

components/copresence/rpc/rpc_handler.cc

@@ -350,7 +350,8 @@ void RpcHandler::RegisterResponseHandler(
     int http_status_code,
     const std::string& response_data) {
   if (completed_post) {
-    DCHECK(pending_posts_.erase(completed_post));
+    int elements_erased = pending_posts_.erase(completed_post);
+    DCHECK(elements_erased);
     delete completed_post;
   }
 
@@ -379,7 +380,8 @@ void RpcHandler::ReportResponseHandler(const StatusCallback& status_callback,
                                        int http_status_code,
                                        const std::string& response_data) {
   if (completed_post) {
-    DCHECK(pending_posts_.erase(completed_post));
+    int elements_erased = pending_posts_.erase(completed_post);
+    DCHECK(elements_erased);
     delete completed_post;
   }