Rework EvaluationResultImpl class hierarchy.

editor/tools/plugins/com.google.dart.engine/src/com/google/dart/engine/internal/hint/DeadCodeVerifier.java

Index: editor/tools/plugins/com.google.dart.engine/src/com/google/dart/engine/internal/hint/DeadCodeVerifier.java
diff --git a/editor/tools/plugins/com.google.dart.engine/src/com/google/dart/engine/internal/hint/DeadCodeVerifier.java b/editor/tools/plugins/com.google.dart.engine/src/com/google/dart/engine/internal/hint/DeadCodeVerifier.java
index 6208d8bcf6eee657b6be106d0603e56c37b1c666..2abedb0835f900c4559289b3330707a38d88233c 100644
--- a/editor/tools/plugins/com.google.dart.engine/src/com/google/dart/engine/internal/hint/DeadCodeVerifier.java
+++ b/editor/tools/plugins/com.google.dart.engine/src/com/google/dart/engine/internal/hint/DeadCodeVerifier.java
@@ -39,7 +39,7 @@ import com.google.dart.engine.element.Element;
 import com.google.dart.engine.element.PropertyAccessorElement;
 import com.google.dart.engine.element.PropertyInducingElement;
 import com.google.dart.engine.error.HintCode;
-import com.google.dart.engine.internal.constant.ValidResult;
+import com.google.dart.engine.internal.constant.EvaluationResultImpl;
 import com.google.dart.engine.internal.error.ErrorReporter;
 import com.google.dart.engine.internal.object.BoolState;
 import com.google.dart.engine.internal.object.DartObjectImpl;
@@ -79,15 +79,15 @@ public class DeadCodeVerifier extends RecursiveAstVisitor<Void> {
     if (isAmpAmp || isBarBar) {
       Expression lhsCondition = node.getLeftOperand();
       if (!isDebugConstant(lhsCondition)) {
-        ValidResult lhsResult = getConstantBooleanValue(lhsCondition);
+        EvaluationResultImpl lhsResult = getConstantBooleanValue(lhsCondition);
         if (lhsResult != null) {
-          if (lhsResult.isTrue() && isBarBar) {
+          if (lhsResult.getValue().isTrue() && isBarBar) {
             // report error on else block: true || !e!
             errorReporter.reportErrorForNode(HintCode.DEAD_CODE, node.getRightOperand());
             // only visit the LHS:
             safelyVisit(lhsCondition);
             return null;
-          } else if (lhsResult.isFalse() && isAmpAmp) {
+          } else if (lhsResult.getValue().isFalse() && isAmpAmp) {
             // report error on if block: false && !e!
             errorReporter.reportErrorForNode(HintCode.DEAD_CODE, node.getRightOperand());
             // only visit the LHS:
@@ -136,9 +136,9 @@ public class DeadCodeVerifier extends RecursiveAstVisitor<Void> {
     Expression conditionExpression = node.getCondition();
     safelyVisit(conditionExpression);
     if (!isDebugConstant(conditionExpression)) {
-      ValidResult result = getConstantBooleanValue(conditionExpression);
+      EvaluationResultImpl result = getConstantBooleanValue(conditionExpression);
       if (result != null) {
-        if (result.isTrue()) {
+        if (result.getValue().isTrue()) {
           // report error on else block: true ? 1 : !2!
           errorReporter.reportErrorForNode(HintCode.DEAD_CODE, node.getElseExpression());
           safelyVisit(node.getThenExpression());
@@ -159,9 +159,9 @@ public class DeadCodeVerifier extends RecursiveAstVisitor<Void> {
     Expression conditionExpression = node.getCondition();
     safelyVisit(conditionExpression);
     if (!isDebugConstant(conditionExpression)) {
-      ValidResult result = getConstantBooleanValue(conditionExpression);
+      EvaluationResultImpl result = getConstantBooleanValue(conditionExpression);
       if (result != null) {
-        if (result.isTrue()) {
+        if (result.getValue().isTrue()) {
           // report error on else block: if(true) {} else {!}
           Statement elseStatement = node.getElseStatement();
           if (elseStatement != null) {
@@ -285,9 +285,9 @@ public class DeadCodeVerifier extends RecursiveAstVisitor<Void> {
     Expression conditionExpression = node.getCondition();
     safelyVisit(conditionExpression);
     if (!isDebugConstant(conditionExpression)) {
-      ValidResult result = getConstantBooleanValue(conditionExpression);
+      EvaluationResultImpl result = getConstantBooleanValue(conditionExpression);
       if (result != null) {
-        if (result.isFalse()) {
+        if (result.getValue().isFalse()) {
           // report error on if block: while (false) {!}
           errorReporter.reportErrorForNode(HintCode.DEAD_CODE, node.getBody());
           return null;
@@ -334,12 +334,12 @@ public class DeadCodeVerifier extends RecursiveAstVisitor<Void> {
    *         if it is {@code false}, or {@code null} if the expression is not a constant boolean
    *         value
    */
-  private ValidResult getConstantBooleanValue(Expression expression) {
+  private EvaluationResultImpl getConstantBooleanValue(Expression expression) {
     if (expression instanceof BooleanLiteral) {
       if (((BooleanLiteral) expression).getValue()) {
-        return new ValidResult(new DartObjectImpl(null, BoolState.from(true)));
+        return new EvaluationResultImpl(new DartObjectImpl(null, BoolState.from(true)));
       } else {
-        return new ValidResult(new DartObjectImpl(null, BoolState.from(false)));
+        return new EvaluationResultImpl(new DartObjectImpl(null, BoolState.from(false)));
       }
     }
     // Don't consider situations where we could evaluate to a constant boolean expression with the