Include source in kernel.

pkg/kernel/binary.md

Index: pkg/kernel/binary.md
diff --git a/pkg/kernel/binary.md b/pkg/kernel/binary.md
index 71b7f33be578d2f26c9a19dd6dc08a236b440055..55ab2e4d292cb850017d0db70e3a29d31fc47b55 100644
--- a/pkg/kernel/binary.md
+++ b/pkg/kernel/binary.md
@@ -59,19 +59,20 @@ type StringReference {
   UInt index; // Index into the StringTable strings.
 }
 
-type LineStarts {
+type LineStartsAndSource {
+  String source;
   // Line starts are delta-encoded (they are encoded as line lengths).  The list
   // [0, 10, 25, 32, 42] is encoded as [0, 10, 15, 7, 10].
   List<Uint> lineStarts;
 }
 
-type UriLineStarts {
+type UriLineStartsAndSource {
   List<String> uris;
-  LineStarts[uris.length] lineStarts;
+  LineStartsAndSource[uris.length] lineStartsAndSource;
 }
 
 type UriReference {
-  UInt index; // Index into the UriLineStarts uris.
+  UInt index; // Index into the UriLineStartsAndSource uris.
 }
 
 type FileOffset {
@@ -93,7 +94,7 @@ type Something<T> extends Option<T> {
 type ProgramFile {
   MagicWord magic = 0x90ABCDEF;
   StringTable strings;
-  UriLineStarts lineStartsMap;
+  UriLineStartsAndSource lineStartsAndSourceMap;
   List<Library> libraries;
   LibraryProcedureReference mainMethod;
 }