simplify AST (idea like)

src/com/google/dart/compiler/backend/js/ast/AbstractNode.java

@@ -1,10 +1,9 @@
 package com.google.dart.compiler.backend.js.ast;
 
 import com.google.dart.compiler.backend.js.JsToStringGenerationVisitor;
-import com.google.dart.compiler.common.HasSourceInfo;
 import com.google.dart.compiler.util.TextOutputImpl;
 
-abstract class AbstractNode implements JsNode, HasSourceInfo {
+abstract class AbstractNode implements JsNode {
     @Override
     public String toString() {
         TextOutputImpl out = new TextOutputImpl();

src/com/google/dart/compiler/backend/js/ast/JsBlock.java

@@ -12,7 +12,7 @@ import java.util.List;
 /**
  * Represents a JavaScript block statement.
  */
-public class JsBlock extends JsNodeImpl implements JsStatement {
+public class JsBlock extends SourceInfoAwareJsNode implements JsStatement {
     private final List<JsStatement> statements;
 
     public JsBlock() {

src/com/google/dart/compiler/backend/js/ast/JsCatch.java

@@ -7,7 +7,7 @@ package com.google.dart.compiler.backend.js.ast;
 /**
  * Represents a JavaScript catch clause.
  */
-public class JsCatch extends JsNodeImpl implements HasCondition {
+public class JsCatch extends SourceInfoAwareJsNode implements HasCondition {
 
     protected final JsCatchScope scope;
     private JsBlock body;

src/com/google/dart/compiler/backend/js/ast/JsContinue.java

@@ -6,7 +6,7 @@ package com.google.dart.compiler.backend.js.ast;
 
 import org.jetbrains.annotations.Nullable;
 
-public class JsContinue extends JsNodeImpl implements JsStatement {
+public class JsContinue extends SourceInfoAwareJsNode implements JsStatement {
     protected final String label;
 
     public JsContinue() {

src/com/google/dart/compiler/backend/js/ast/JsDebugger.java

@@ -7,7 +7,7 @@ package com.google.dart.compiler.backend.js.ast;
 /**
  * Represents a JavaScript debugger statement.
  */
-public class JsDebugger extends JsNodeImpl implements JsStatement {
+public class JsDebugger extends SourceInfoAwareJsNode implements JsStatement {
     public JsDebugger() {
     }
 

src/com/google/dart/compiler/backend/js/ast/JsEmpty.java

@@ -4,7 +4,7 @@
 
 package com.google.dart.compiler.backend.js.ast;
 
-public class JsEmpty extends JsNodeImpl implements JsStatement {
+public class JsEmpty extends SourceInfoAwareJsNode implements JsStatement {
     JsEmpty() {
     }
 

src/com/google/dart/compiler/backend/js/ast/JsExpressionImpl.java

@@ -6,10 +6,7 @@ package com.google.dart.compiler.backend.js.ast;
 
 import java.util.List;
 
-abstract class JsExpressionImpl extends JsNodeImpl implements JsExpression {
-    protected JsExpressionImpl() {
-    }
-
+abstract class JsExpressionImpl extends SourceInfoAwareJsNode implements JsExpression {
     /**
      * Determines whether or not this expression is a leaf, such as a
      * {@link JsNameRef}, {@link JsLiteral.JsBooleanLiteral}, and so on. Leaf expressions

src/com/google/dart/compiler/backend/js/ast/JsFor.java

@@ -15,7 +15,7 @@ package com.google.dart.compiler.backend.js.ast;
  * Note that any of the parts of the <code>for</code> loop header can be
  * <code>null</code>, although the body will never be null.
  */
-public class JsFor extends JsNodeImpl implements JsStatement {
+public class JsFor extends SourceInfoAwareJsNode implements JsStatement {
     private JsStatement body;
     private JsExpression condition;
     private JsExpression incrementExpression;

src/com/google/dart/compiler/backend/js/ast/JsForIn.java

@@ -4,7 +4,7 @@
 
 package com.google.dart.compiler.backend.js.ast;
 
-public class JsForIn extends JsNodeImpl implements JsStatement {
+public class JsForIn extends SourceInfoAwareJsNode implements JsStatement {
     private JsStatement body;
     private JsExpression iterExpression;
     private JsExpression objectExpression;

src/com/google/dart/compiler/backend/js/ast/JsIf.java

@@ -7,7 +7,7 @@ package com.google.dart.compiler.backend.js.ast;
 /**
  * Represents a JavaScript if statement.
  */
-public final class JsIf extends JsNodeImpl implements JsStatement {
+public final class JsIf extends SourceInfoAwareJsNode implements JsStatement {
     private JsExpression ifExpression;
     private JsStatement thenStatement;
     private JsStatement elseStatement;

src/com/google/dart/compiler/backend/js/ast/JsLabel.java

@@ -9,7 +9,7 @@ import com.google.dart.compiler.common.Symbol;
 /**
  * Represents a JavaScript label statement.
  */
-public class JsLabel extends JsNodeImpl implements JsStatement, HasName {
+public class JsLabel extends SourceInfoAwareJsNode implements JsStatement, HasName {
     private final JsName label;
 
     private JsStatement statement;

src/com/google/dart/compiler/backend/js/ast/JsParameter.java

@@ -9,7 +9,7 @@ import com.google.dart.compiler.common.Symbol;
 /**
  * A JavaScript parameter.
  */
-public final class JsParameter extends JsNodeImpl implements HasName {
+public final class JsParameter extends SourceInfoAwareJsNode implements HasName {
     private final JsName name;
 
     public JsParameter(JsName name) {

src/com/google/dart/compiler/backend/js/ast/JsProgram.java

@@ -17,7 +17,7 @@ import static com.google.dart.compiler.backend.js.ast.JsNumberLiteral.JsIntLiter
 /**
  * A JavaScript program.
  */
-public final class JsProgram extends JsNodeImpl {
+public final class JsProgram extends SourceInfoAwareJsNode {
     private final JsEmpty emptyStatement;
 
     private JsProgramFragment[] fragments;

src/com/google/dart/compiler/backend/js/ast/JsProgramFragment.java

@@ -7,7 +7,7 @@ package com.google.dart.compiler.backend.js.ast;
 /**
  * One independently loadable fragment of a {@link JsProgram}.
  */
-public class JsProgramFragment extends JsNodeImpl {
+public class JsProgramFragment extends SourceInfoAwareJsNode {
     private final JsGlobalBlock globalBlock;
 
     public JsProgramFragment() {

src/com/google/dart/compiler/backend/js/ast/JsPropertyInitializer.java

@@ -9,7 +9,7 @@ import org.jetbrains.annotations.NotNull;
 /**
  * Used in object literals to specify property values by name.
  */
-public class JsPropertyInitializer extends JsNodeImpl {
+public class JsPropertyInitializer extends SourceInfoAwareJsNode {
     private JsExpression labelExpr;
     private JsExpression valueExpr;
 

src/com/google/dart/compiler/backend/js/ast/JsReturn.java

@@ -7,7 +7,7 @@ package com.google.dart.compiler.backend.js.ast;
 /**
  * A JavaScript return statement.
  */
-public final class JsReturn extends JsNodeImpl implements JsStatement {
+public final class JsReturn extends SourceInfoAwareJsNode implements JsStatement {
     private JsExpression expression;
 
     public JsReturn() {

src/com/google/dart/compiler/backend/js/ast/JsSwitch.java

@@ -10,7 +10,7 @@ import java.util.List;
 /**
  * A JavaScript switch statement.
  */
-public class JsSwitch extends JsNodeImpl implements JsStatement {
+public class JsSwitch extends SourceInfoAwareJsNode implements JsStatement {
 
     private final List<JsSwitchMember> cases = new ArrayList<JsSwitchMember>();
     private JsExpression expression;

src/com/google/dart/compiler/backend/js/ast/JsSwitchMember.java

@@ -11,7 +11,7 @@ import java.util.List;
 /**
  * A member/case in a JavaScript switch object.
  */
-public abstract class JsSwitchMember extends JsNodeImpl {
+public abstract class JsSwitchMember extends SourceInfoAwareJsNode {
     protected final List<JsStatement> statements = new SmartList<JsStatement>();
 
     protected JsSwitchMember() {

src/com/google/dart/compiler/backend/js/ast/JsThrow.java

@@ -4,7 +4,7 @@
 
 package com.google.dart.compiler.backend.js.ast;
 
-public class JsThrow extends JsNodeImpl implements JsStatement {
+public class JsThrow extends SourceInfoAwareJsNode implements JsStatement {
     private JsExpression expression;
 
     public JsThrow() {

src/com/google/dart/compiler/backend/js/ast/JsTry.java

@@ -12,7 +12,7 @@ import java.util.List;
 /**
  * A JavaScript <code>try</code> statement.
  */
-public class JsTry extends JsNodeImpl implements JsStatement {
+public class JsTry extends SourceInfoAwareJsNode implements JsStatement {
     private final List<JsCatch> catches;
     private JsBlock finallyBlock;
     private JsBlock tryBlock;

src/com/google/dart/compiler/backend/js/ast/JsVars.java

@@ -16,7 +16,7 @@ import java.util.List;
 /**
  * A JavaScript <code>var</code> statement.
  */
-public class JsVars extends JsNodeImpl implements JsStatement, Iterable<JsVars.JsVar> {
+public class JsVars extends SourceInfoAwareJsNode implements JsStatement, Iterable<JsVars.JsVar> {
     private final List<JsVar> vars;
 
     private final boolean multiline;
@@ -49,7 +49,7 @@ public class JsVars extends JsNodeImpl implements JsStatement, Iterable<JsVars.J
     /**
      * A var declared using the JavaScript <code>var</code> statement.
      */
-    public static class JsVar extends JsNodeImpl implements HasName {
+    public static class JsVar extends SourceInfoAwareJsNode implements HasName {
         private final JsName name;
         private JsExpression initExpression;
 

src/com/google/dart/compiler/backend/js/ast/JsWhile.java

@@ -7,7 +7,7 @@ package com.google.dart.compiler.backend.js.ast;
 /**
  * A JavaScript <code>while</code> statement.
  */
-public class JsWhile extends JsNodeImpl implements JsStatement {
+public class JsWhile extends SourceInfoAwareJsNode implements JsStatement {
     protected JsStatement body;
     protected JsExpression condition;
 

src/com/google/dart/compiler/backend/js/ast/SourceInfoAwareJsNode.java

@@ -1,11 +1,8 @@
 package com.google.dart.compiler.backend.js.ast;
 
-abstract class JsNodeImpl extends AbstractNode {
+abstract class SourceInfoAwareJsNode extends AbstractNode {
     private Object sourceInfo;
 
-    protected JsNodeImpl() {
-    }
-
     @Override
     public Object getSourceInfo() {
         return sourceInfo;