Revert "Add optional message to assert in Dart2js - continued"

sdk/lib/_internal/js_runtime/lib/js_helper.dart

Index: sdk/lib/_internal/js_runtime/lib/js_helper.dart
diff --git a/sdk/lib/_internal/js_runtime/lib/js_helper.dart b/sdk/lib/_internal/js_runtime/lib/js_helper.dart
index 309f255f7a75d48a2fe662fcede9a3bab75e4d9e..b4ab91c192b236631901ea56dfd63960692ea18a 100644
--- a/sdk/lib/_internal/js_runtime/lib/js_helper.dart
+++ b/sdk/lib/_internal/js_runtime/lib/js_helper.dart
@@ -3321,33 +3321,18 @@ class FallThroughErrorImplementation extends FallThroughError {
 
 /**
  * Helper function for implementing asserts. The compiler treats this specially.
- *
- * Returns the negation of the condition. That is: `true` if the assert should
- * fail.
- */
-bool assertTest(condition) {
-  // Do bool success check first, it is common and faster than 'is Function'.
-  if (true == condition) return false;
-  if (condition is Function) condition = condition();
-  if (condition is bool) return !condition;
-  throw new TypeErrorImplementation(condition, 'bool');
-}
-
-/**
- * Helper function for implementing asserts with messages.
- * The compiler treats this specially.
  */
-void assertThrow(Object message) {
-  throw new _AssertionError(message);
-}
-
-/**
- * Helper function for implementing asserts without messages.
- * The compiler treats this specially.
- */
-@NoInline()
 void assertHelper(condition) {
-  if (assertTest(condition)) throw new AssertionError();
+  // Do a bool check first because it is common and faster than 'is Function'.
+  if (condition is !bool) {
+    if (condition is Function) condition = condition();
+    if (condition is !bool) {
+      throw new TypeErrorImplementation(condition, 'bool');
+    }
+  }
+  // Compare to true to avoid boolean conversion check in checked
+  // mode.
+  if (true != condition) throw new AssertionError();
 }
 
 /**
@@ -4010,10 +3995,3 @@ void badMain() {
 void mainHasTooManyParameters() {
   throw new MainError("'main' expects too many parameters.");
 }
-
-class _AssertionError extends AssertionError {
-  final _message;
-  _AssertionError(this._message);
-
-  String toString() => "Assertion failed: " + Error.safeToString(_message);
-}