Revert "Implement override checks."

lib/compiler/implementation/compiler.dart

Index: lib/compiler/implementation/compiler.dart
diff --git a/lib/compiler/implementation/compiler.dart b/lib/compiler/implementation/compiler.dart
index 5cb19337cb4fcc308c118fca646646309eb21ecd..6a78ae5e1f127347aa970adbc7507e675cef653c 100644
--- a/lib/compiler/implementation/compiler.dart
+++ b/lib/compiler/implementation/compiler.dart
@@ -303,8 +303,6 @@ class Compiler implements DiagnosticListener {
   static final int PHASE_RECOMPILING = 3;
   int phase;
 
-  bool compilationFailed = false;
-
   Compiler([this.tracer = const Tracer(),
             this.enableTypeAssertions = false,
             this.enableUserAssertions = false,
@@ -550,8 +548,6 @@ class Compiler implements DiagnosticListener {
     processQueue(enqueuer.resolution, main);
     log('Resolved ${enqueuer.resolution.resolvedElements.length} elements.');
 
-    if (compilationFailed) return;
-
     log('Compiling...');
     phase = PHASE_COMPILING;
     processQueue(enqueuer.codegen, main);
@@ -561,8 +557,6 @@ class Compiler implements DiagnosticListener {
     processRecompilationQueue(enqueuer.codegen);
     log('Compiled ${codegenWorld.generatedCode.length} methods.');
 
-    if (compilationFailed) return;
-
     backend.assembleProgram();
 
     checkQueues();
@@ -761,7 +755,7 @@ class Compiler implements DiagnosticListener {
     }
     SourceSpan span = spanFromNode(node);
 
-    reportDiagnostic(span, 'Warning: $message', api.Diagnostic.WARNING);
+    reportDiagnostic(span, 'Warning: $message', api.Diagnostic.WARNING );
   }
 
   reportError(Node node, var message) {
@@ -770,14 +764,6 @@ class Compiler implements DiagnosticListener {
     throw new CompilerCancelledException(message.toString());
   }
 
-  void reportMessage(SourceSpan span,
-                     Diagnostic message,
-                     api.Diagnostic kind) {
-    // TODO(ahe): The names Diagnostic and api.Diagnostic are in
-    // conflict. Fix it.
-    reportDiagnostic(span, "$message", kind);
-  }
-
   abstract void reportDiagnostic(SourceSpan span, String message,
                                  api.Diagnostic kind);