Make SourceInfo a class, rename its menthods.

compiler/java/com/google/dart/compiler/parser/DartParser.java

Index: compiler/java/com/google/dart/compiler/parser/DartParser.java
diff --git a/compiler/java/com/google/dart/compiler/parser/DartParser.java b/compiler/java/com/google/dart/compiler/parser/DartParser.java
index 0fc36b335e28c5e9b3d8859c1d8754043df374a2..ccd91a316966be5b6406f33429cd10052124e19a 100644
--- a/compiler/java/com/google/dart/compiler/parser/DartParser.java
+++ b/compiler/java/com/google/dart/compiler/parser/DartParser.java
@@ -1245,10 +1245,10 @@ public class DartParser extends CompletionHooksParserBase {
     if (method.getModifiers().isGetter() || method.getModifiers().isSetter()) {
       DartField field = new DartField((DartIdentifier) method.getName(),
                                       method.getModifiers().makeAbstractField(), method, null);
-      field.setSourceInfo(method);
+      field.setSourceInfo(method.getSourceInfo());
       DartFieldDefinition fieldDefinition =
         new DartFieldDefinition(null, Lists.<DartField>create(field));
-      fieldDefinition.setSourceInfo(field);
+      fieldDefinition.setSourceInfo(field.getSourceInfo());
       return fieldDefinition;
     }
     // OK, use method as method.
@@ -3666,7 +3666,7 @@ public class DartParser extends CompletionHooksParserBase {
     }
 
     if ( catches.size() == 0 && finallyBlock == null) {
-      reportError(new DartCompilationError(tryBlock.getSource(), new Location(position()),
+      reportError(new DartCompilationError(tryBlock.getSourceInfo().getSource(), new Location(position()),
         ParserErrorCode.CATCH_OR_FINALLY_EXPECTED));
     }