apple: Remove --format=json from plist conversion scripts.

We don't seem to use it, and it makes it easier to implement these
scripts without subprocess calls using just plistlib once on Py3.

Bug: 1147069
Change-Id: Iac7464b7767b2c221f3a63bf79708aa211147249
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2554781Reviewed-by: Sylvain Defresne <sdefresne@chromium.org>
Commit-Queue: Sylvain Defresne <sdefresne@chromium.org>
Auto-Submit: Nico Weber <thakis@chromium.org>
Cr-Commit-Position: refs/heads/master@{#830519}

build/apple/tweak_info_plist.py

@@ -278,7 +278,7 @@ def Main(argv):
       'like key=value (can be passed multiple time to configure '
       'more than one override)')
   parser.add_option('--format',
-                    choices=('binary1', 'xml1', 'json'),
+                    choices=('binary1', 'xml1'),
                     default='xml1',
                     help='Format to use when writing property list '
                     '(default: %(default)s)')

build/config/mac/plist_util.py

@@ -178,7 +178,7 @@ class MergeAction(Action):
         '-o', '--output', required=True,
         help='path to the output plist file')
     parser.add_argument(
-        '-f', '--format', required=True, choices=('xml1', 'binary1', 'json'),
+        '-f', '--format', required=True, choices=('xml1', 'binary1'),
         help='format of the plist file to generate')
     parser.add_argument(
         '-x',
@@ -214,7 +214,7 @@ class SubstituteAction(Action):
         '-s', '--substitution', action='append', default=[],
         help='substitution rule in the format key=value')
     parser.add_argument(
-        '-f', '--format', required=True, choices=('xml1', 'binary1', 'json'),
+        '-f', '--format', required=True, choices=('xml1', 'binary1'),
         help='format of the plist file to generate')
     parser.add_argument(
         '-x',