Add --add-new-files option to download-baselines.py script

This will allow the user to determine whether the script downloads just
updates for baselines that are already checked in, or all available baselines.

BUG=436
addresses http://code.google.com/p/skia/issues/detail?id=436 ('add "update" flag to download-baselines script')
Review URL: http://codereview.appspot.com/5523050

git-svn-id: http://skia.googlecode.com/svn/trunk@2993 2bbb7eff-a529-9590-31e7-b0007b416f81
diff --git a/tools/svn.py b/tools/svn.py
index e878301..ab811aa 100644
--- a/tools/svn.py
+++ b/tools/svn.py
@@ -39,7 +39,16 @@
         SVN control.
         """
         stdout = self._RunCommand(['svn', 'status'])
-        new_regex = re.compile('\? +(.+)')
+        new_regex = re.compile('^\?.....\s+(.+)$', re.MULTILINE)
+        files = new_regex.findall(stdout)
+        return files
+
+    def GetNewAndModifiedFiles(self):
+        """Return a list of files in this dir which are newly added or modified,
+        including those that are not (yet) under SVN control.
+        """
+        stdout = self._RunCommand(['svn', 'status'])
+        new_regex = re.compile('^[AM\?].....\s+(.+)$', re.MULTILINE)
         files = new_regex.findall(stdout)
         return files