Compressing .pak resources with new option: "type=GZIPPABLE_BINDATA"

tools/grit/grit/node/include.py

Index: tools/grit/grit/node/include.py
diff --git a/tools/grit/grit/node/include.py b/tools/grit/grit/node/include.py
index 4780d5e8425b475a5956028bbcfd832b3dd29c05..39e226e7ff97d084094b571dcb50ab60a4259252 100755
--- a/tools/grit/grit/node/include.py
+++ b/tools/grit/grit/node/include.py
@@ -7,16 +7,21 @@
 """
 
 import os
+import sys
 
+from grit import exception
+from grit import util
+import grit.format.gzip_string
 import grit.format.html_inline
-import grit.format.rc_header
 import grit.format.rc
-
+import grit.format.rc_header
 from grit.node import base
-from grit import util
 
 class IncludeNode(base.Node):
   """An <include> element."""
+
+  RESERVED_HEADER = '\xff\x1f\x8b'
+
   def __init__(self):
     super(IncludeNode, self).__init__()
 
@@ -38,7 +43,6 @@ class IncludeNode(base.Node):
               preprocess_only=False,
               allow_external_script=allow_external_script))
     return self._flattened_data
-
   def MandatoryAttributes(self):
     return ['name', 'type', 'file']
 
@@ -48,6 +52,7 @@ class IncludeNode(base.Node):
             'filenameonly': 'false',
             'mkoutput': 'false',
             'flattenhtml': 'false',
+            'compress': 'false',
             'allowexternalscript': 'false',
             'relativepath': 'false',
             'use_base_dir': 'true',
@@ -91,6 +96,23 @@ class IncludeNode(base.Node):
       filename = self.ToRealPath(self.GetInputPath())
       data = util.ReadFile(filename, util.BINARY)
 
+    if 'compress' in self.attrs and self.attrs['compress'] == 'gzip':
+      # We only use rsyncable compression on Linux.
+      if sys.platform == 'linux2':
+        data = grit.format.gzip_string.GzipStringRsyncable(data)
+      else:
+        data = grit.format.gzip_string.GzipString(data)
+      data = self.RESERVED_HEADER[0] + data
+    elif data[:3] == self.RESERVED_HEADER:
+      # We are reserving these 3 bytes as the header for gzipped files in the
+      # data pack. 1f:8b is the first two bytes of a gzipped header, and ff is
+      # a custom byte we throw in front of the gzip header so that we prevent
+      # accidentally throwing this error on a resource we gzipped beforehand and
+      # don't wish to compress again. If this exception is hit, change the first
+      # byte of RESERVED_HEADER, and then mirror that update in
+      # ui/base/resource/resource_bundle.h
+      raise exception.ReservedHeaderCollision();
+
     # Include does not care about the encoding, because it only returns binary
     # data.
     return id, data