Revert "Compute frontend/backend specific constants."

sdk/lib/_internal/compiler/implementation/mirrors_used.dart

Index: sdk/lib/_internal/compiler/implementation/mirrors_used.dart
diff --git a/sdk/lib/_internal/compiler/implementation/mirrors_used.dart b/sdk/lib/_internal/compiler/implementation/mirrors_used.dart
index 276cab2e50b5ceb631aa6710a4809fcdb5f732c3..034d2094b6d0fb3089ede39ea14327e6b3ce05f8 100644
--- a/sdk/lib/_internal/compiler/implementation/mirrors_used.dart
+++ b/sdk/lib/_internal/compiler/implementation/mirrors_used.dart
@@ -8,7 +8,6 @@ import 'dart2jslib.dart' show
     Compiler,
     CompilerTask,
     Constant,
-    ConstantCompiler,
     ConstructedConstant,
     ListConstant,
     MessageKind,
@@ -134,13 +133,17 @@ class MirrorUsageAnalyzerTask extends CompilerTask {
     for (Node argument in node.send.arguments) {
       NamedArgument named = argument.asNamedArgument();
       if (named == null) continue;
-      ConstantCompiler constantCompiler = compiler.resolver.constantCompiler;
-      Constant value = constantCompiler.compileNode(named.expression, mapping);
+      Constant value = compiler.constantHandler.compileNodeWithDefinitions(
+          named.expression, mapping, isConst: true);
+
+      ConstantMapper mapper =
+          new ConstantMapper(compiler.constantHandler, mapping, compiler);
+      named.expression.accept(mapper);
 
       MirrorUsageBuilder builder =
           new MirrorUsageBuilder(
               analyzer, mapping.currentElement.getLibrary(), named.expression,
-              value, mapping);
+              value, mapper.constantToNodeMap);
 
       if (named.name.source == 'symbols') {
         analyzer.cachedStrings[value] =
@@ -371,14 +374,14 @@ class MirrorUsageBuilder {
   final LibraryElement enclosingLibrary;
   final Spannable spannable;
   final Constant constant;
-  final TreeElements elements;
+  final Map<Constant, Node> constantToNodeMap;
 
   MirrorUsageBuilder(
       this.analyzer,
       this.enclosingLibrary,
       this.spannable,
       this.constant,
-      this.elements);
+      this.constantToNodeMap);
 
   Compiler get compiler => analyzer.compiler;
 
@@ -563,12 +566,7 @@ class MirrorUsageBuilder {
 
   /// Attempt to find a [Spannable] corresponding to constant.
   Spannable positionOf(Constant constant) {
-    Node node;
-    elements.forEachConstantNode((Node n, Constant c) {
-      if (node == null && c == constant) {
-        node = n;
-      }
-    });
+    Node node = constantToNodeMap[constant];
     if (node == null) {
       // TODO(ahe): Returning [spannable] here leads to confusing error
       // messages.  For example, consider: