Fix up proguard output filtering

build/android/gyp/util/proguard_util.py

Index: build/android/gyp/util/proguard_util.py
diff --git a/build/android/gyp/util/proguard_util.py b/build/android/gyp/util/proguard_util.py
index 8ca86462631939eb0f44eb2b506b8e508e5fe762..78f44d9f4c1f83b2d37b87f505179e571060b6e5 100644
--- a/build/android/gyp/util/proguard_util.py
+++ b/build/android/gyp/util/proguard_util.py
@@ -3,29 +3,33 @@
 # found in the LICENSE file.
 
 import os
+import re
 from util import build_utils
 
-def FilterProguardOutput(output):
-  '''ProGuard outputs boring stuff to stdout (proguard version, jar path, etc)
+
+class _ProguardOutputFilter(object):
+  """ProGuard outputs boring stuff to stdout (proguard version, jar path, etc)
   as well as interesting stuff (notes, warnings, etc). If stdout is entirely
-  boring, this method suppresses the output.
-  '''
-  ignore_patterns = [
-    'ProGuard, version ',
-    'Reading program jar [',
-    'Reading library jar [',
-    'Preparing output jar [',
-    '  Copying resources from program jar [',
-  ]
-  for line in output.splitlines():
-    for pattern in ignore_patterns:
-      if line.startswith(pattern):
-        break
-    else:
-      # line doesn't match any of the patterns; it's probably something worth
-      # printing out.
-      return output
-  return ''
+  boring, this class suppresses the output.
+  """
+
+  IGNORE_RE = re.compile(
+      r'(Pro.*version|Note:|Reading|Preparing|.*:.*(MANIFEST\.MF|\.empty))')

[Nico, 2016/01/05 19:53:07]

nit: consider non-capturing groups (?:asdf) since you don't need the capture

[agrieve, 2016/01/05 20:53:24]

Done.

+
+  def __init__(self):
+    self._last_line_ignored = False
+
+  def __call__(self, output):
+    ret = []
+    for line in output.splitlines(True):

[Nico, 2016/01/05 19:53:07]

nit: consider always naming bool parameters (splitlines(keepends=True))

[agrieve, 2016/01/05 20:53:24]

I did actually try that, but it gives me:
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
TypeError: splitlines() takes no keyword arguments

+      if not line.startswith(' '):
+        self._last_line_ignored = bool(self.IGNORE_RE.match(line))
+      elif 'You should check if you need to specify' in line:
+        self._last_line_ignored = True

[Nico, 2016/01/05 19:53:07]

This keeps

Maybe this is program method 'android.support.v4.text.ICUCompatIcs {
java.lang.String getScript(java.lang.String); }'

lines, right?

[agrieve, 2016/01/05 20:53:24]

It hides them because in this case the line starts with a ' ' and does not match
the elif either. It's treated as a continuation of the previous line, which
looks like "Note: ..."

Tested that for a chrome_apk release build this hides all output.

+
+      if not self._last_line_ignored:
+        ret.append(line)
+    return ''.join(ret)
 
 
 class ProguardCmdBuilder(object):
@@ -145,7 +149,7 @@ class ProguardCmdBuilder(object):
     return inputs
 
 
-  def CheckOutput(self):
+  def CheckOutput(self, verbose=False):
     self.build()
     # Proguard will skip writing these files if they would be empty. Create
     # empty versions of them all now so that they are updated as the build
@@ -154,8 +158,17 @@ class ProguardCmdBuilder(object):
     open(self._outjar + '.seeds', 'w').close()
     open(self._outjar + '.usage', 'w').close()
     open(self._outjar + '.mapping', 'w').close()
+    # Warning: and Error: are sent to stderr, but messages and Note: are sent
+    # to stdout.
+    stdout_filter = None
+    stderr_filter = None
+    if not verbose:
+      stdout_filter = _ProguardOutputFilter()
+      stderr_filter = _ProguardOutputFilter()
     build_utils.CheckOutput(self._cmd, print_stdout=True,
-                            stdout_filter=FilterProguardOutput)
+                            print_stderr=True,
+                            stdout_filter=stdout_filter,
+                            stderr_filter=stderr_filter)
 
     this_info = {
       'inputs': self._injars,