Clean up error handling.

dart/tests/compiler/dart2js/analyze_only_test.dart

Index: dart/tests/compiler/dart2js/analyze_only_test.dart
diff --git a/dart/tests/compiler/dart2js/analyze_only_test.dart b/dart/tests/compiler/dart2js/analyze_only_test.dart
index 34e52c7b3965c980a0e41b68d4012cc128733726..6ab98674ddef88c6b453afb68882e313b34f27b8 100644
--- a/dart/tests/compiler/dart2js/analyze_only_test.dart
+++ b/dart/tests/compiler/dart2js/analyze_only_test.dart
@@ -53,7 +53,7 @@ main() {
     (String code, List errors, List warnings) {
       Expect.isNull(code);
       Expect.equals(1, errors.length);
-      Expect.equals('Could not find main', errors[0].toString());
+      Expect.equals('Error: Could not find "main".', errors[0].toString());
       Expect.isTrue(warnings.isEmpty);
     });
 
@@ -72,7 +72,8 @@ main() {
     (String code, List errors, List warnings) {
       Expect.isNull(code);
       Expect.equals(1, errors.length);
-      Expect.isTrue(errors[0].toString().startsWith('Could not find main'));
+      Expect.isTrue(
+          errors[0].toString().startsWith('Error: Could not find "main".'));
       Expect.isTrue(warnings.isEmpty);
     });
 
@@ -91,7 +92,8 @@ main() {
     (String code, List errors, List warnings) {
       Expect.isNull(code);
       Expect.equals(1, errors.length);
-      Expect.isTrue(errors[0].toString().startsWith('Could not find main'));
+      Expect.isTrue(
+          errors[0].toString().startsWith('Error: Could not find "main".'));
       Expect.isTrue(warnings.isEmpty);
     });
 
@@ -104,7 +106,8 @@ main() {
       Expect.isNull(code);
       Expect.isTrue(errors.isEmpty);
       Expect.equals(1, warnings.length);
-      Expect.equals('Warning: cannot resolve type Foo', warnings[0].toString());
+      Expect.equals(
+          'Warning: Cannot resolve type "Foo".', warnings[0].toString());
     });
 
   runCompiler(
@@ -124,7 +127,8 @@ main() {
     (String code, List errors, List warnings) {
       Expect.isNull(code);
       Expect.isTrue(errors.isEmpty);
-      Expect.equals('Warning: cannot resolve type Foo', warnings[0].toString());
+      Expect.equals(
+          'Warning: Cannot resolve type "Foo".', warnings[0].toString());
     });
 
   runCompiler(
@@ -135,7 +139,8 @@ main() {
       Expect.isNull(code);
       Expect.isTrue(errors.isEmpty);
       Expect.equals(1, warnings.length);
-      Expect.equals('Warning: cannot resolve type Foo', warnings[0].toString());
+      Expect.equals(
+          'Warning: Cannot resolve type "Foo".', warnings[0].toString());
     });
 
   runCompiler(