--- a/reviewboard/reviewboard/diffviewer/parser.py
+++ b/reviewboard/reviewboard/diffviewer/parser.py
@@ -2,16 +2,17 @@ from __future__ import unicode_literals
 
 import logging
 import re
 
 from django.utils import six
 from django.utils.six.moves import range
 
 from reviewboard.diffviewer.errors import DiffParserError
+from reviewboard.extensions.fixuphook import DownloadRawHook
 
 
 class File(object):
     def __init__(self):
         self.origFile = None
         self.newFile = None
         self.origInfo = None
         self.newInfo = None
@@ -224,17 +225,20 @@ class DiffParser(object):
                               "found in the diff header",
                               linenum)
 
     def raw_diff(self, diffset):
         """Returns a raw diff as a string.
 
         The returned diff as composed of all FileDiffs in the provided diffset.
         """
-        return b''.join([filediff.diff for filediff in diffset.files.all()])
+        files = diffset.files.all()
+        for hook in DownloadRawHook.hooks:
+            files = hook.filter(files)
+        return b''.join([filediff.diff for filediff in files])
 
     def get_orig_commit_id(self):
         """Returns the commit ID of the original revision for the diff.
 
         This is overridden by tools that only use commit IDs, not file
         revision IDs.
         """
         return None

new file mode 100644
--- /dev/null
+++ b/reviewboard/reviewboard/extensions/fixuphook.py
@@ -0,0 +1,11 @@
+from django.utils import six
+
+from djblets.extensions.hooks import (ExtensionHook, ExtensionHookPoint)
+
+
+@six.add_metaclass(ExtensionHookPoint)
+class DownloadRawHook(ExtensionHook):
+    """A hook to modify the download raw content."""
+    def filter(self, files):
+        """Returns a diffset ready to display."""
+        raise NotImplementedError