Make SourceInfo a class, rename its menthods.

editor/tools/plugins/com.google.dart.tools.core/src/com/google/dart/tools/core/internal/model/LibraryConfigurationFileImpl.java

Index: editor/tools/plugins/com.google.dart.tools.core/src/com/google/dart/tools/core/internal/model/LibraryConfigurationFileImpl.java
diff --git a/editor/tools/plugins/com.google.dart.tools.core/src/com/google/dart/tools/core/internal/model/LibraryConfigurationFileImpl.java b/editor/tools/plugins/com.google.dart.tools.core/src/com/google/dart/tools/core/internal/model/LibraryConfigurationFileImpl.java
index 169bd5c1ce0c04c1d529cd182d6f2f5688ca0f2d..2d838d228d433f4e8a86e5b95467a11b38978798 100644
--- a/editor/tools/plugins/com.google.dart.tools.core/src/com/google/dart/tools/core/internal/model/LibraryConfigurationFileImpl.java
+++ b/editor/tools/plugins/com.google.dart.tools.core/src/com/google/dart/tools/core/internal/model/LibraryConfigurationFileImpl.java
@@ -97,12 +97,12 @@ public class LibraryConfigurationFileImpl extends SourceFileElementImpl<LibraryC
       //this loop is to make sure we're inserting in alphabetical order
       isEmpty = false;
       LibraryNode node = itr.next();
-      pos = node.getSourceStart();
+      pos = node.getSourceInfo().getOffset();
       if (node.getText().compareTo(name) > 0) {
         isLast = false;
         break;
       }
-      pos += node.getSourceLength();
+      pos += node.getSourceInfo().getLength();
     }
     Buffer buffer = getBuffer();
     String whole = buffer.getContents();
@@ -142,12 +142,12 @@ public class LibraryConfigurationFileImpl extends SourceFileElementImpl<LibraryC
       //this loop is to make sure we're inserting in alphabetical order
       isEmpty = false;
       LibraryNode node = itr.next();
-      pos = node.getSourceStart();
+      pos = node.getSourceInfo().getOffset();
       if (node.getText().compareTo(name) > 0) {
         isLast = false;
         break;
       }
-      pos += node.getSourceLength();
+      pos += node.getSourceInfo().getLength();
     }
     Buffer buffer = getBuffer();
     String whole = buffer.getContents();