Make all DDC internal stack traces apply source maps.

pkg/dev_compiler/lib/js/legacy/dart_sdk.js

Index: pkg/dev_compiler/lib/js/legacy/dart_sdk.js
diff --git a/pkg/dev_compiler/lib/js/legacy/dart_sdk.js b/pkg/dev_compiler/lib/js/legacy/dart_sdk.js
index ff6fe1080a7e87723e1285d17c5ed8eb8b3b3acd..b508b31f103bc40fe976ad385ee3ee9836d9b563 100644
--- a/pkg/dev_compiler/lib/js/legacy/dart_sdk.js
+++ b/pkg/dev_compiler/lib/js/legacy/dart_sdk.js
@@ -4072,6 +4072,13 @@ dart_library.library('dart_sdk', null, /* Imports */[
       children: dart.definiteFunctionType(core.List$(_debugger.NameValuePair), [dart.dynamic])
     })
   });
+  _debugger.StackTraceMapper = dart.typedef('StackTraceMapper', () => dart.functionType(core.String, [core.String]));
+  dart.copyProperties(_debugger, {
+    get stackTraceMapper() {
+      let _util = dart.global.$dartStackTraceUtility;
+      return _debugger.StackTraceMapper._check(_util != null ? _util.mapper : null);
+    }
+  });
   _debugger.registerDevtoolsFormatter = function() {
     let formatters = JSArrayOfJsonMLFormatter().of([_debugger._devtoolsFormatter]);
     dart.global.devtoolsFormatters = formatters;
@@ -11941,6 +11948,9 @@ dart_library.library('dart_sdk', null, /* Imports */[
       let trace = null;
       if (this[_exception] !== null && typeof this[_exception] === "object") {
         trace = this[_exception].stack;
+        if (trace != null && _debugger.stackTraceMapper != null) {
+          trace = _debugger.stackTraceMapper(trace);
+        }
       }
       return this[_trace] = trace == null ? '' : trace;
     }