Use function name from stack if we don't have one in the source map

This is always the case atm since we're not parsing function names from
source maps yet.

Author: sebmarkbage

packages/react-devtools-shared/src/devtools/views/Components/StackTraceView.js

@@ -33,7 +33,8 @@ type CallSiteViewProps = {
 export function CallSiteView({callSite}: CallSiteViewProps): React.Node {
   const fetchFileWithCaching = useContext(FetchFileWithCachingContext);
 
-  const [, virtualURL, virtualLine, virtualColumn] = callSite;
+  const [virtualFunctionName, virtualURL, virtualLine, virtualColumn] =
+    callSite;
 
   const symbolicatedCallSite: null | ReactFunctionLocation =
     fetchFileWithCaching !== null
@@ -55,7 +56,7 @@ export function CallSiteView({callSite}: CallSiteViewProps): React.Node {
     symbolicatedCallSite !== null ? symbolicatedCallSite : callSite;
   return (
     <div className={styles.CallSite}>
-      {functionName}
+      {functionName || virtualFunctionName}
       {' @ '}
       <span
         className={linkIsEnabled ? styles.Link : null}