Python readability review for dbeam@.

This simplifies the python closure compiler infrastructure.

R=rothwell@google.com

Review URL: https://codereview.chromium.org/476453002

Cr-Commit-Position: refs/heads/master@{#322255}

third_party/closure_compiler/compile_js.gypi

@@ -38,6 +38,7 @@
         '--depends', '<@(depends)',
         '--externs', '<@(externs)',
         '--out_file', '<(out_file)',
+        # Add '--verbose', for glorious log spam.
       ],
       'message': 'Compiling <(source_file)',
     }

third_party/closure_compiler/compiler_customization_test.py

@@ -36,18 +36,17 @@ class CompilerCustomizationTest(unittest.TestCase):
     return self._checker.check(file_path)
 
   def _runCheckerTestExpectError(self, source_code, expected_error):
-    _, output = self._runChecker(source_code)
+    _, stderr = self._runChecker(source_code)
 
-    self.assertTrue(expected_error in output,
+    self.assertTrue(expected_error in stderr,
         msg="Expected chunk: \n%s\n\nOutput:\n%s\n" % (
-            expected_error, output))
+            expected_error, stderr))
 
   def _runCheckerTestExpectSuccess(self, source_code):
-    return_code, output = self._runChecker(source_code)
+    found_errors, stderr = self._runChecker(source_code)
 
-    self.assertTrue(return_code == 0,
-        msg="Expected success, got return code %d\n\nOutput:\n%s\n" % (
-            return_code, output))
+    self.assertFalse(found_errors,
+        msg="Expected success, but got failure\n\nOutput:\n%s\n" % stderr)
 
   def testGetInstance(self):
     self._runCheckerTestExpectError("""

third_party/closure_compiler/processor.py

@@ -10,13 +10,13 @@ import os
 
 
 class LineNumber(object):
-  """A simple wrapper to hold line information (e.g. file.js:32).
-  
-  Args:
-    source_file: A file path.
-    line_number: The line in |file|.
-  """
+  """A simple wrapper to hold line information (e.g. file.js:32)."""
   def __init__(self, source_file, line_number):
+    """
+    Args:
+      source_file: A file path (as a string).
+      line_number: The line in |file| (as an integer).
+    """
     self.file = source_file
     self.line_number = int(line_number)
 
@@ -25,7 +25,7 @@ class FileCache(object):
   """An in-memory cache to speed up reading the same files over and over.
   
   Usage:
-      FileCache.read(path_to_file)
+    FileCache.read(path_to_file)
   """
 
   _cache = defaultdict(str)
@@ -35,10 +35,10 @@ class FileCache(object):
     """Read a file and return it as a string.
 
     Args:
-        source_file: a file to read and return the contents of.
+      source_file: a file path (as a string) to read and return the contents.
 
     Returns:
-        |file| as a string.
+      The contents of |source_file| (as a string).
     """
     abs_file = os.path.abspath(source_file)
     self._cache[abs_file] = self._cache[abs_file] or open(abs_file, "r").read()
@@ -51,42 +51,40 @@ class Processor(object):
 
   For example
 
-      1: /* blah.js */
-      2: <if expr="is_win">
-      3: <include src="win.js">
-      4: </if>
+    1: /* blah.js */
+    2: <if expr="is_win">
+    3: <include src="win.js">
+    4: </if>
 
   would be turned into:
 
-      1: /* blah.js */
-      2:
-      3: /* win.js */
-      4: alert('Ew; Windows.');
-      5:
-
-  Args:
-      source_file: A file to process.
-
-  Attributes:
-      contents: Expanded contents after inlining <include>s and stripping <if>s.
-      included_files: A list of files that were inlined via <include>.
+    1: /* blah.js */
+    2:
+    3: /* win.js */
+    4: alert('Ew; Windows.');
+    5:
   """
 
   _IF_TAGS_REG = "</?if[^>]*?>"
   _INCLUDE_REG = "<include[^>]+src=['\"]([^>]*)['\"]>"
 
   def __init__(self, source_file):
-    self._included_files = set()
+    """
+    Args:
+      source_file: A file path to process (as a string).
+    """
+    self.included_files = set()
     self._index = 0
     self._lines = self._get_file(source_file)
 
+    # Can't enumerate(self._lines) here because some lines are re-processed.
     while self._index < len(self._lines):
       current_line = self._lines[self._index]
       match = re.search(self._INCLUDE_REG, current_line[2])
       if match:
         file_dir = os.path.dirname(current_line[0])
         file_name = os.path.abspath(os.path.join(file_dir, match.group(1)))
-        if file_name not in self._included_files:
+        if file_name not in self.included_files:
           self._include_file(file_name)
           continue  # Stay on the same line.
         else:
@@ -106,7 +104,7 @@ class Processor(object):
     return [(source_file, lnum + 1, line) for lnum, line in enumerate(lines)]
 
   def _include_file(self, source_file):
-    self._included_files.add(source_file)
+    self.included_files.add(source_file)
     f = self._get_file(source_file)
     self._lines = self._lines[:self._index] + f + self._lines[self._index + 1:]
 
@@ -114,12 +112,7 @@ class Processor(object):
     """Get the original file and line number for an expanded file's line number.
 
     Args:
-        line_number: A processed file's line number.
+      line_number: A processed file's line number (as an integer or string).
     """
     line_number = int(line_number) - 1
     return LineNumber(self._lines[line_number][0], self._lines[line_number][1])
-
-  @property
-  def included_files(self):
-    """A list of files that were inlined via <include>."""
-    return self._included_files