[ddc, test_runner] Add stackTrace debugger helper to dartDevEmbedder and clean up test_runner

Adds a stackTrace helper that returns a stringified StackTrace for
an arbitrary error. Removes importLibrary references in test_runner
now that we have that and removes some calls that didn't do anything
(addAsyncCallback, removeAsyncCallback, and startRootIsolate).

addAsyncCallback and removeAsyncCallback are also removed from the
runtime. Calling these were removed in 8bd3690
so this is just finishing up the clean-up.

Change-Id: I9dacc2b3fd3e27468061d6e59a3207eecdb7cac8
Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/393800
Reviewed-by: Nicholas Shahan <[email protected]>
Commit-Queue: Srujan Gaddam <[email protected]>
Reviewed-by: Bob Nystrom <[email protected]>

Author: srujzs

pkg/dev_compiler/lib/js/ddc/ddc_module_loader.js

@@ -1909,6 +1909,18 @@ if (!self.deferred_loader) {
     get extensionNames() {
       return dartDeveloperLibrary()._extensions.keys().toList();
     }
+
+    /**
+     * Returns a Dart stack trace string given an error caught in JS. If the
+     * error is a Dart error or JS `Error`, we use the built-in stack. If the
+     * error is neither, we try to construct a stack trace if possible.
+     *
+     * @param {any} error The error for which a stack trace will be produced.
+     * @returns {String} The stringified stack trace.
+     */
+    stackTrace(error) {
+      return dartRuntimeLibrary().stackTrace(error).toString();
+    }
   }
 
   const debugger_ = new Debugger();

pkg/test_runner/lib/src/browser.dart

@@ -172,11 +172,10 @@ String ddcHtml(
   var hotReloadFormat = ddcModuleFormat && canaryMode;
 
   var sdkAndAsyncHelperSetup = """
-_isolate_helper.startRootIsolate(function() {}, []);
 _debugger.registerDevtoolsFormatter();
 
 testErrorToStackTrace = function(error) {
-  var stackTrace = runtime.stackTrace(error).toString();
+  var stackTrace = getStackTraceString(error);
 
   var lines = stackTrace.split("\\n");
 
@@ -195,19 +194,6 @@ testErrorToStackTrace = function(error) {
   // lines too.
   return lines.join("\\n");
 };
-
-runtime.addAsyncCallback = function() {
-  expect.async_helper.asyncStart();
-};
-
-runtime.removeAsyncCallback = function() {
-  // removeAsyncCallback() is called *before* the async operation is
-  // performed, but we don't want to report the test as being done until
-  // after that operation completes, so wait for that callback to run.
-  setTimeout(() => {
-    expect.async_helper.asyncEnd();
-  }, 0);
-};
 """;
 
   var sdkFlagSetup = """
@@ -232,12 +218,11 @@ runtime.jsInteropNonNullAsserts($jsInteropNonNullAsserts);
     String libraryImports;
     String startCode;
     if (hotReloadFormat) {
-      var import = 'dartDevEmbedder.importLibrary';
       libraryImports = """
-        let runtime = $import("dart:_runtime");
-        let expect = $import("package:expect/async_helper.dart");
-        let _isolate_helper = $import("dart:_isolate_helper");
-        let _debugger = $import("dart:_debugger");
+        let _debugger = dartDevEmbedder.debugger;
+        let getStackTraceString = function(error) {
+          return _debugger.stackTrace(error);
+        }
       """;
       sdkFlagSetup = """
         let sdkOptions = {
@@ -255,8 +240,9 @@ runtime.jsInteropNonNullAsserts($jsInteropNonNullAsserts);
       libraryImports = """
         let sdk = dart_library.import("dart_sdk", "$appName");
         let runtime = sdk.dart;
-        let expect = dart_library.import("expect", "$appName");
-        let _isolate_helper = sdk._isolate_helper;
+        let getStackTraceString = function(error) {
+          return runtime.stackTrace(error).toString();
+        }
         let _debugger = sdk._debugger;
       """;
       startCode = """dart_library.start("$appName", "$uuid", "$testName",
@@ -305,10 +291,11 @@ $packagePaths
 <script type="text/javascript"
         src="/root_dart/third_party/requirejs/require.js"></script>
 <script type="text/javascript">
-requirejs(["$testName", "dart_sdk", "expect"],
-    function($testId, sdk, expect) {
+requirejs(["$testName", "dart_sdk"], function($testId, sdk) {
   let runtime = sdk.dart;
-  let _isolate_helper = sdk._isolate_helper;
+  let getStackTraceString = function(error) {
+    return runtime.stackTrace(error).toString();
+  }
   let _debugger = sdk._debugger;
 
   $sdkAndAsyncHelperSetup

sdk/lib/_internal/js_dev_runtime/private/ddc_runtime/runtime.dart

@@ -275,18 +275,3 @@ void hotRestart() {
     JS('', '#.clear()', deferredImports);
   }
 }
-
-/// Marks enqueuing an async operation.
-///
-/// This will be called by library code when enqueuing an async operation
-/// controlled by the JavaScript event handler.
-///
-/// It will also call [removeAsyncCallback] when Dart callback is about to be
-/// executed (note this is called *before* the callback executes, so more
-/// async operations could be added from that).
-void Function() addAsyncCallback = JS('', 'function() {}');
-
-/// Marks leaving a javascript async operation.
-///
-/// See [addAsyncCallback].
-void Function() removeAsyncCallback = JS('', 'function() {}');