Revert "Compute frontend/backend specific constants."

sdk/lib/_internal/compiler/implementation/js_emitter/code_emitter_task.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 dart2js.js_emitter;
 
 /**
  * Generates the code for all used classes in the program. Static fields (even
  * in classes) are ignored, since they can be treated as non-class elements.
  *
@@ skipping 824 matching lines @@
         backend.generatedCode.keys.where(isStaticFunction);
 
     for (Element element in Elements.sortedByPosition(elements)) {
       ClassBuilder builder = new ClassBuilder(namer);
       containerBuilder.addMember(element, builder);
       getElementDecriptor(element).properties.addAll(builder.properties);
     }
   }
 
   void emitStaticNonFinalFieldInitializations(CodeBuffer buffer) {
-    JavaScriptConstantCompiler handler = backend.constants;
+    ConstantHandler handler = compiler.constantHandler;
     Iterable<VariableElement> staticNonFinalFields =
         handler.getStaticNonFinalFieldsForEmission();
     for (Element element in Elements.sortedByPosition(staticNonFinalFields)) {
       // [:interceptedNames:] is handled in [emitInterceptedNames].
       if (element == backend.interceptedNames) continue;
       // `mapTypeToInterceptor` is handled in [emitMapTypeToInterceptor].
       if (element == backend.mapTypeToInterceptor) continue;
       compiler.withCurrentElement(element, () {
         Constant initialValue = handler.getInitialValueFor(element);
         jsAst.Expression init =
           js('$isolateProperties.${namer.getNameOfGlobalField(element)} = #',
               constantEmitter.referenceInInitializationContext(initialValue));
         buffer.write(jsAst.prettyPrint(init, compiler));
         buffer.write('$N');
       });
     }
   }
 
   void emitLazilyInitializedStaticFields(CodeBuffer buffer) {
-    JavaScriptConstantCompiler handler = backend.constants;
+    ConstantHandler handler = compiler.constantHandler;
     List<VariableElement> lazyFields =
         handler.getLazilyInitializedFieldsForEmission();
     if (!lazyFields.isEmpty) {
       needsLazyInitializer = true;
       for (VariableElement element in Elements.sortedByPosition(lazyFields)) {
         jsAst.Expression code = backend.generatedCode[element];
         // The code is null if we ended up not needing the lazily
         // initialized field after all because of constant folding
         // before code generation.
         if (code == null) continue;
@@ skipping 18 matching lines @@
       }
     }
   }
 
   jsAst.Expression buildLazyInitializedGetter(VariableElement element) {
     // Nothing to do, the 'lazy' function will create the getter.
     return null;
   }
 
   void emitCompileTimeConstants(CodeBuffer buffer, OutputUnit outputUnit) {
-    JavaScriptConstantCompiler handler = backend.constants;
+    ConstantHandler handler = compiler.constantHandler;
     List<Constant> constants = handler.getConstantsForEmission(
         compareConstants);
     Set<Constant> outputUnitConstants = null;
     // TODO(sigurdm): We shouldn't run through all constants for every
     // outputUnit.
     for (Constant constant in constants) {
       if (isConstantInlinedOrAlreadyEmitted(constant)) continue;
       OutputUnit constantUnit =
           compiler.deferredLoadTask.outputUnitForConstant(constant);
       if (constantUnit != outputUnit && constantUnit != null) continue;
@@ skipping 786 matching lines @@
     String sourceMap = sourceMapBuilder.build(compiledFile);
     compiler.outputProvider(name, 'js.map')
         ..add(sourceMap)
         ..close();
   }
 
   void registerReadTypeVariable(TypeVariableElement element) {
     readTypeVariables.add(element);
   }
 }