Restore the accidentally deleted extra_check_functions in cpplint.py

This extra parameter was used when calling cpplint.ProcessFile
directly from depot_tools/gcl.py and depot_tools/git_cl.py.

Restoring it...

[email protected]

Review URL: https://codereview.appspot.com/105820044

cpplint/cpplint.py

@@ -5289,7 +5289,8 @@ def CheckDefaultLambdaCaptures(filename, clean_lines, linenum, error):
 
 
 def ProcessLine(filename, file_extension, clean_lines, line,
-                include_state, function_state, nesting_state, error):
+                include_state, function_state, nesting_state, error,
+                extra_check_functions=[]):
   """Processes a single line in the file.
 
   Args:
@@ -5304,7 +5305,9 @@ def ProcessLine(filename, file_extension, clean_lines, line,
                    the current stack of nested blocks being parsed.
     error: A callable to which errors are reported, which takes 4 arguments:
            filename, line number, error level, and message
-
+    extra_check_functions: An array of additional check functions that will be
+                           run on each source line. Each function takes 4
+                           arguments: filename, clean_lines, line, error
   """
   raw_lines = clean_lines.raw_lines
   ParseNolintSuppressions(filename, raw_lines[line], line, error)
@@ -5323,8 +5326,9 @@ def ProcessLine(filename, file_extension, clean_lines, line,
   CheckInvalidIncrement(filename, clean_lines, line, error)
   CheckMakePairUsesDeduction(filename, clean_lines, line, error)
   CheckDefaultLambdaCaptures(filename, clean_lines, line, error)
-
-
+  for check_fn in extra_check_functions:
+    check_fn(filename, clean_lines, line, error)
+
 def FlagCxx11Features(filename, clean_lines, linenum, error):
   """Flag those c++11 features that we only allow in certain places.
 
@@ -5374,7 +5378,8 @@ def FlagCxx11Features(filename, clean_lines, linenum, error):
              'they may let you use it.') % top_name)
 
 
-def ProcessFileData(filename, file_extension, lines, error):
+def ProcessFileData(filename, file_extension, lines, error,
+                    extra_check_functions=[]):
   """Performs lint checks and reports any errors to the given error function.
 
   Args:
@@ -5383,6 +5388,10 @@ def ProcessFileData(filename, file_extension, lines, error):
     lines: An array of strings, each representing a line of the file, with the
            last element being empty if the file is terminated with a newline.
     error: A callable to which errors are reported, which takes 4 arguments:
+           filename, line number, error level, and message
+    extra_check_functions: An array of additional check functions that will be
+                           run on each source line. Each function takes 4
+                           arguments: filename, clean_lines, line, error
   """
   lines = (['// marker so line numbers and indices both start at 1'] + lines +
            ['// marker so line numbers end in a known way'])
@@ -5402,7 +5411,8 @@ def ProcessFileData(filename, file_extension, lines, error):
   clean_lines = CleansedLines(lines)
   for line in xrange(clean_lines.NumLines()):
     ProcessLine(filename, file_extension, clean_lines, line,
-                include_state, function_state, nesting_state, error)
+                include_state, function_state, nesting_state, error,
+                extra_check_functions)
     FlagCxx11Features(filename, clean_lines, line, error)
   nesting_state.CheckCompletedBlocks(filename, error)
 
@@ -5415,14 +5425,18 @@ def ProcessFileData(filename, file_extension, lines, error):
   CheckForNewlineAtEOF(filename, lines, error)
 
 
-def ProcessFile(filename, vlevel):
+def ProcessFile(filename, vlevel, extra_check_functions=[]):
   """Does google-lint on a single file.
 
   Args:
     filename: The name of the file to parse.
 
     vlevel: The level of errors to report.  Every error of confidence
     >= verbose_level will be reported.  0 is a good default.
+
+    extra_check_functions: An array of additional check functions that will be
+                           run on each source line. Each function takes 4
+                           arguments: filename, clean_lines, line, error
   """
 
   _SetVerboseLevel(vlevel)
@@ -5468,7 +5482,8 @@ def ProcessFile(filename, vlevel):
     sys.stderr.write('Ignoring %s; not a valid file name '
                      '(%s)\n' % (filename, ', '.join(_valid_extensions)))
   else:
-    ProcessFileData(filename, file_extension, lines, Error)
+    ProcessFileData(filename, file_extension, lines, Error,
+                    extra_check_functions)
 
     # If end-of-line sequences are a mix of LF and CR-LF, issue
     # warnings on the lines with CR.