dart2js: Allow 'throw' when inlining

sdk/lib/_internal/compiler/implementation/js_backend/backend.dart

Index: sdk/lib/_internal/compiler/implementation/js_backend/backend.dart
diff --git a/sdk/lib/_internal/compiler/implementation/js_backend/backend.dart b/sdk/lib/_internal/compiler/implementation/js_backend/backend.dart
index a2cffcf2f09c84d36757f28e83471cb10a9e35a2..57d4b3e8072aec3de148248d1690f7dfc1dc90f0 100644
--- a/sdk/lib/_internal/compiler/implementation/js_backend/backend.dart
+++ b/sdk/lib/_internal/compiler/implementation/js_backend/backend.dart
@@ -1139,6 +1139,10 @@ class JavaScriptBackend extends Backend {
     enqueueInResolution(getThrowHelper(), elements);
   }
 
+  void registerThrowExpression(TreeElements elements) {
+    enqueueInResolution(getThrowExpressionHelper(), elements);
+  }
+
   void registerLazyField(TreeElements elements) {
     enqueueInResolution(getCyclicThrowHelper(), elements);
   }
@@ -1676,6 +1680,10 @@ class JavaScriptBackend extends Backend {
     return compiler.findHelper(const SourceString(r'$throw'));
   }
 
+  Element getThrowExpressionHelper() {
+    return compiler.findHelper(const SourceString('throwExpression'));
+  }
+
   Element getClosureConverter() {
     return compiler.findHelper(const SourceString('convertDartClosureToJS'));
   }