grit: minify json outputs

This can easily save ~1k if not ~10k+ per message file.  Looking at an
example CrOS image today, this can add up to MB of data in the rootfs.

We don't make this optional for now as it's not clear whether anyone
really cares, and it's easy enough for people to pretty print the json
files after the fact.

Bug: 852585
Change-Id: I1d2331dfc38d404ea03facd3d0a8845f32c4f981
Reviewed-on: https://chromium-review.googlesource.com/c/1320515Reviewed-by: Robert Flack <flackr@chromium.org>
Commit-Queue: Mike Frysinger <vapier@chromium.org>
Cr-Commit-Position: refs/heads/master@{#608146}

tools/grit/grit/format/chrome_messages_json.py

@@ -15,15 +15,11 @@ from grit.node import message
 
 def Format(root, lang='en', output_dir='.'):
   """Format the messages as JSON."""
-  yield '{\n'
+  yield '{'
 
   encoder = JSONEncoder(ensure_ascii=False)
-  format = ('  "%s": {\n'
-            '    "message": %s%s\n'
-            '  }')
-  placeholder_format = ('      "%i": {\n'
-                        '        "content": "$%i"\n'
-                        '      }')
+  format = '"%s":{"message":%s%s}'
+  placeholder_format = '"%i":{"content":"$%i"}'
   first = True
   for child in root.ActiveDescendants():
     if isinstance(child, message.MessageNode):
@@ -50,15 +46,15 @@ def Format(root, lang='en', output_dir='.'):
           break
         loc_message = loc_message.replace('$%d' % i, '$%d$' % i)
         if placeholders:
-          placeholders += ',\n'
+          placeholders += ','
         placeholders += placeholder_format % (i, i)
 
       if not first:
-        yield ',\n'
+        yield ','
       first = False
 
       if placeholders:
-        placeholders = ',\n    "placeholders": {\n%s\n    }' % placeholders
+        placeholders = ',"placeholders":{%s}' % placeholders
       yield format % (id, loc_message, placeholders)
 
-  yield '\n}\n'
+  yield '}'

tools/grit/grit/format/chrome_messages_json_unittest.py

@@ -6,6 +6,7 @@
 """Unittest for chrome_messages_json.py.
 """
 
+import json
 import os
 import sys
 if __name__ == '__main__':
@@ -20,6 +21,10 @@ from grit.tool import build
 
 class ChromeMessagesJsonFormatUnittest(unittest.TestCase):
 
+  # The default unittest diff limit is too low for our unittests.
+  # Allow the framework to show the full diff output all the time.
+  maxDiff = None
+
   def testMessages(self):
     root = util.ParseGrdForUnittest(u"""
     <messages>
@@ -96,7 +101,7 @@ class ChromeMessagesJsonFormatUnittest(unittest.TestCase):
   }
 }
 """
-    self.assertEqual(test.strip(), output.strip())
+    self.assertEqual(json.loads(test), json.loads(output))
 
   def testTranslations(self):
     root = util.ParseGrdForUnittest("""
@@ -121,7 +126,7 @@ class ChromeMessagesJsonFormatUnittest(unittest.TestCase):
   }
 }
 """
-    self.assertEqual(test.strip(), output.strip())
+    self.assertEqual(json.loads(test), json.loads(output))
 
   def testSkipMissingTranslations(self):
     grd = """<?xml version="1.0" encoding="UTF-8"?>
@@ -141,12 +146,25 @@ class ChromeMessagesJsonFormatUnittest(unittest.TestCase):
     build.RcBuilder.ProcessNode(root, DummyOutput('chrome_messages_json', 'fr'),
                                 buf)
     output = buf.getvalue()
-    test = u"""
-{
+    test = u'{}'
+    self.assertEqual(test, output)
 
-}
-"""
-    self.assertEqual(test.strip(), output.strip())
+  def testVerifyMinification(self):
+    root = util.ParseGrdForUnittest(u"""
+    <messages>
+      <message name="IDS">
+        <ph name="BEGIN">$1<ex>a</ex></ph>test<ph name="END">$2<ex>b</ex></ph>
+      </message>
+    </messages>
+    """)
+
+    buf = StringIO.StringIO()
+    build.RcBuilder.ProcessNode(root, DummyOutput('chrome_messages_json', 'en'),
+                                buf)
+    output = buf.getvalue()
+    test = (u'{"IDS":{"message":"$1$test$2$","placeholders":'
+            u'{"1":{"content":"$1"},"2":{"content":"$2"}}}}')
+    self.assertEqual(test, output)
 
 
 class DummyOutput(object):