Updated *.pak file format to support both UTF8 and UTF16

tools/grit/grit/format/data_pack.py

Index: tools/grit/grit/format/data_pack.py
diff --git a/tools/grit/grit/format/data_pack.py b/tools/grit/grit/format/data_pack.py
index 993ecf63fd127f3709eb5c26500cb366ebc209d1..e8d88077f56a818957f967ec419d911878a7bc68 100755
--- a/tools/grit/grit/format/data_pack.py
+++ b/tools/grit/grit/format/data_pack.py
@@ -15,8 +15,8 @@ from grit.node import message
 from grit.node import misc
 
 
-PACK_FILE_VERSION = 3
-
+PACK_FILE_VERSION = 4
+BINARY, UTF8, UTF16 = range(3)
 
 class DataPack(interface.ItemFormatter):
   '''Writes out the data pack file format (platform agnostic resource file).'''
@@ -29,9 +29,9 @@ class DataPack(interface.ItemFormatter):
     nodes = DataPack.GetDataNodes(item)
     data = {}
     for node in nodes:
-      id, value = node.GetDataPackPair(lang)
+      id, value = node.GetDataPackPair(lang, UTF8)
       data[id] = value
-    return DataPack.WriteDataPack(data)
+    return DataPack.WriteDataPack(data, UTF8)
 
   @staticmethod
   def GetDataNodes(item):
@@ -50,15 +50,15 @@ class DataPack(interface.ItemFormatter):
     return nodes
 
   @staticmethod
-  def WriteDataPack(resources):
+  def WriteDataPack(resources, encoding):
     """Write a map of id=>data into a string in the data pack format and return
     it."""
     ids = sorted(resources.keys())
     ret = []
 
     # Write file header.
-    ret.append(struct.pack("<II", PACK_FILE_VERSION, len(ids)))
-    HEADER_LENGTH = 2 * 4             # Two uint32s.
+    ret.append(struct.pack("<IIB", PACK_FILE_VERSION, len(ids), encoding))
+    HEADER_LENGTH = 2 * 4 + 1            # Two uint32s and one uint8.
 
     # Each entry is a uint16 + a uint32s. We have one extra entry for the last
     # item.