mozbuild: Encode content of GeneratedFile.

python/mozbuild/mozpack/files.py

@@ -489,7 +489,10 @@ class GeneratedFile(BaseFile):
     File class for content with no previous existence on the filesystem.
     '''
     def __init__(self, content):
-        self.content = content
+        if isinstance(content, str):
+            self.content = content.encode()
+        else:
+            self.content = content
 
     def open(self, mode='rb'):
         if 'b' in mode:

toolkit/mozapps/installer/packager.py

@@ -192,7 +192,7 @@ class RemovedFiles(GeneratedFile):
             return
         if self.copier.contains(f):
             errors.error('Removal of packaged file(s): %s' % f)
-        self.content += f + '\n'
+        self.content += f.encode() + b'\n'
 
 
 def split_define(define):