Gets rid of some warnings in the analyzer for unused code and unused imports

compiler/java/com/google/dart/compiler/resolver/CompileTimeConstantAnalyzer.java

Index: compiler/java/com/google/dart/compiler/resolver/CompileTimeConstantAnalyzer.java
diff --git a/compiler/java/com/google/dart/compiler/resolver/CompileTimeConstantAnalyzer.java b/compiler/java/com/google/dart/compiler/resolver/CompileTimeConstantAnalyzer.java
index 475379524568806ba530b53be5ec29afa5c76ac2..27bdb64342aa9a2c21736d43d878c04459b14293 100644
--- a/compiler/java/com/google/dart/compiler/resolver/CompileTimeConstantAnalyzer.java
+++ b/compiler/java/com/google/dart/compiler/resolver/CompileTimeConstantAnalyzer.java
@@ -13,7 +13,6 @@ import com.google.dart.compiler.InternalCompilerException;
 import com.google.dart.compiler.ast.ASTVisitor;
 import com.google.dart.compiler.ast.DartArrayLiteral;
 import com.google.dart.compiler.ast.DartBinaryExpression;
-import com.google.dart.compiler.ast.DartBlock;
 import com.google.dart.compiler.ast.DartBooleanLiteral;
 import com.google.dart.compiler.ast.DartClass;
 import com.google.dart.compiler.ast.DartDeclaration;
@@ -27,7 +26,6 @@ import com.google.dart.compiler.ast.DartIntegerLiteral;
 import com.google.dart.compiler.ast.DartInvocation;
 import com.google.dart.compiler.ast.DartMapLiteral;
 import com.google.dart.compiler.ast.DartMapLiteralEntry;
-import com.google.dart.compiler.ast.DartMethodDefinition;
 import com.google.dart.compiler.ast.DartMethodInvocation;
 import com.google.dart.compiler.ast.DartNamedExpression;
 import com.google.dart.compiler.ast.DartNewExpression;
@@ -152,7 +150,7 @@ public class CompileTimeConstantAnalyzer {
      */
     private Type getMostSpecificType(DartNode node) {
       if (node != null) {
-        Element element = (Element) node.getElement();
+        Element element = node.getElement();
         Type type = inferredTypes.get(node);
         if (type != null) {
           return type;
@@ -267,7 +265,7 @@ public class CompileTimeConstantAnalyzer {
           rememberInferredType(x, intType);
         } else if (lhsType.equals(doubleType) && rhsType.equals(doubleType)) {
           rememberInferredType(x, doubleType);
-        } else  if (lhsType.equals(doubleType) && rhsType.equals(intType) 
+        } else  if (lhsType.equals(doubleType) && rhsType.equals(intType)
             || lhsType.equals(intType) && rhsType.equals(doubleType)) {
           rememberInferredType(x, doubleType);
         } else {
@@ -350,7 +348,7 @@ public class CompileTimeConstantAnalyzer {
           if (!element.getModifiers().isConstant() && !element.getModifiers().isFinal()) {
             expectedConstant(x);
           }
-          
+
           // Infer type by visiting node or cached from Element.
           final Type inferredType;
           if (element instanceof FieldNodeElement) {
@@ -359,19 +357,19 @@ public class CompileTimeConstantAnalyzer {
             fieldNode.accept(this);
             inferredType = getMostSpecificType(fieldNode);
             fieldNodeElement.setConstantType(inferredType);
-          } else if (fieldElement.getType() != null 
+          } else if (fieldElement.getType() != null
               && !fieldElement.getType().equals(dynamicType)) {
             inferredType = fieldElement.getType();
           } else {
             inferredType = fieldElement.getConstantType();
           }
-          
+
           // Done with this element.
           visitedElements.remove(element);
 
           rememberInferredType(x, inferredType);
           break;
-          
+
         case METHOD:
           if (!element.getModifiers().isStatic() && !Elements.isTopLevel(element)) {
             expectedConstant(x);