Add optional message to assert in Dart2js.

pkg/compiler/lib/src/js_backend/backend.dart

 // Copyright (c) 2012, the Dart project authors.  Please see the AUTHORS file
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
 part of js_backend;
 
 const VERBOSE_OPTIMIZER_HINTS = false;
 
 class JavaScriptItemCompilationContext extends ItemCompilationContext {
   final Set<HInstruction> boundsChecked = new Set<HInstruction>();
@@ skipping 260 matching lines @@
   FunctionInlineCache inlineCache = new FunctionInlineCache();
 
   LibraryElement jsHelperLibrary;
   LibraryElement asyncLibrary;
   LibraryElement interceptorsLibrary;
   LibraryElement foreignLibrary;
   LibraryElement isolateHelperLibrary;
 
   ClassElement closureClass;
   ClassElement boundClosureClass;
-  Element assertMethod;
+  Element assertTestMethod;
+  Element assertThrowMethod;
+  Element assertHelperMethod;
   Element invokeOnMethod;
 
   ClassElement jsInterceptorClass;
   ClassElement jsStringClass;
   ClassElement jsArrayClass;
   ClassElement jsNumberClass;
   ClassElement jsIntClass;
   ClassElement jsDoubleClass;
   ClassElement jsNullClass;
   ClassElement jsBoolClass;
@@ skipping 1055 matching lines @@
         Element element = find(isolateHelperLibrary, name);
         enqueuer.addToWorkList(element);
         compiler.globalDependencies.registerDependency(element);
         helpersUsed.add(element.declaration);
       }
     } else {
       enqueuer.addToWorkList(find(isolateHelperLibrary, START_ROOT_ISOLATE));
     }
   }
 
-  bool isAssertMethod(Element element) => element == assertMethod;
-
   void registerRequiredType(DartType type, Element enclosingElement) {
     // If [argument] has type variables or is a type variable, this method
     // registers a RTI dependency between the class where the type variable is
     // defined (that is the enclosing class of the current element being
     // resolved) and the class of [type]. If the class of [type] requires RTI,
     // then the class of the type variable does too.
     ClassElement contextClass = Types.getClassContext(type);
     if (contextClass != null) {
       assert(contextClass == enclosingElement.enclosingClass.declaration);
       rti.registerRtiDependency(type.element, contextClass);
@@ skipping 753 matching lines @@
         jsMutableArrayClass = findClass('JSMutableArray');
         jsFixedArrayClass = findClass('JSFixedArray');
         jsExtendableArrayClass = findClass('JSExtendableArray');
         jsUnmodifiableArrayClass = findClass('JSUnmodifiableArray');
         jsPlainJavaScriptObjectClass = findClass('PlainJavaScriptObject');
         jsUnknownJavaScriptObjectClass = findClass('UnknownJavaScriptObject');
         jsIndexableClass = findClass('JSIndexable');
         jsMutableIndexableClass = findClass('JSMutableIndexable');
       } else if (uri == DART_JS_HELPER) {
         initializeHelperClasses();
-        assertMethod = findHelper('assertHelper');
+        assertTestMethod = findHelper('assertTest');
+        assertThrowMethod = findHelper('assertThrow');
+        assertHelperMethod = findHelper('assertHelper');
 
         typeLiteralClass = findClass('TypeImpl');
         constMapLiteralClass = findClass('ConstantMap');
         typeVariableClass = findClass('TypeVariable');
 
         jsIndexingBehaviorInterface = findClass('JavaScriptIndexingBehavior');
 
         noSideEffectsClass = findClass('NoSideEffects');
         noThrowsClass = findClass('NoThrows');
         noInlineClass = findClass('NoInline');
@@ skipping 776 matching lines @@
   void registerBackendStaticInvocation(Element element, Registry registry) {
     registry.registerStaticInvocation(backend.registerBackendUse(element));
   }
 
   void registerBackendInstantiation(ClassElement element, Registry registry) {
     backend.registerBackendUse(element);
     element.ensureResolved(backend.compiler);
     registry.registerInstantiation(element.rawType);
   }
 
-  void onAssert(Send node, Registry registry) {
-    registerBackendStaticInvocation(backend.assertMethod, registry);
+  void onAssert(bool hasMessage, Registry registry) {
+    if (hasMessage) {
+      registerBackendStaticInvocation(backend.assertTestMethod, registry);
+      registerBackendStaticInvocation(backend.assertThrowMethod, registry);
+    } else {
+      registerBackendStaticInvocation(backend.assertHelperMethod, registry);
+    }
   }
 
   void onAsyncForIn(AsyncForIn node, Registry registry) {
     registerBackendStaticInvocation(backend.getStreamIteratorConstructor(),
                                     registry);
   }
 
   void onStringInterpolation(Registry registry) {
     assert(registry.isForResolution);
     registerBackendStaticInvocation(
@@ skipping 194 matching lines @@
   }
 }
 
 /// Records that [constant] is used by the element behind [registry].
 class Dependency {
   final ConstantValue constant;
   final Element annotatedElement;
 
   const Dependency(this.constant, this.annotatedElement);
 }