Add deduplication logic to .pak files

tools/grit/pak_util.py

Index: tools/grit/pak_util.py
diff --git a/tools/grit/pak_util.py b/tools/grit/pak_util.py
index ec43f33afddae2c0d22756bb76e8903a7b40f3a2..97f70647c497c4fd405a0ae780d8606172d371d3 100755
--- a/tools/grit/pak_util.py
+++ b/tools/grit/pak_util.py
@@ -33,6 +33,7 @@ def _ExtractMain(args):
 
 def _PrintMain(args):
   pak = data_pack.ReadDataPack(args.pak_file)
+  id_map = {id(v): k for k, v in sorted(pak.resources.items(), reverse=True)}
   encoding = 'binary'
   if pak.encoding == 1:
     encoding = 'utf-8'
@@ -57,8 +58,13 @@ def _PrintMain(args):
       except UnicodeDecodeError:
         pass
     sha1 = hashlib.sha1(data).hexdigest()[:10]
-    line = u'Entry(id={}, len={}, sha1={}): {}'.format(
-        resource_id, len(data), sha1, desc)
+    canonical_id = id_map[id(data)]
+    if resource_id == canonical_id:
+      line = u'Entry(id={}, len={}, sha1={}): {}'.format(
+          resource_id, len(data), sha1, desc)
+    else:
+      line = u'Entry(id={}, alias_of={}): {}'.format(
+          resource_id, canonical_id, desc)
     print line.encode('utf-8')