Skip commits that don't generate a patch + fixes to get export working

third_party/WebKit/Tools/Scripts/webkitpy/w3c/chromium_commit.py

Index: third_party/WebKit/Tools/Scripts/webkitpy/w3c/chromium_commit.py
diff --git a/third_party/WebKit/Tools/Scripts/webkitpy/w3c/chromium_commit.py b/third_party/WebKit/Tools/Scripts/webkitpy/w3c/chromium_commit.py
index f87cb43cd21552d27d9a21fb4265e8c312794431..8eef0a28923951da1b8ed4b4a05958ac2ff41609 100644
--- a/third_party/WebKit/Tools/Scripts/webkitpy/w3c/chromium_commit.py
+++ b/third_party/WebKit/Tools/Scripts/webkitpy/w3c/chromium_commit.py
@@ -5,6 +5,8 @@
 from webkitpy.common.memoized import memoized
 from webkitpy.common.webkit_finder import WebKitFinder
 
+WPT_DIR = 'third_party/WebKit/LayoutTests/imported/wpt/'
+
 
 class ChromiumCommit(object):
 
@@ -63,14 +65,31 @@ class ChromiumCommit(object):
 
     def format_patch(self):
         """Makes a patch with just changes in files in the WPT for a given commit."""
+
+        # Get list of changed files
+        changed_files = self.host.executive.run_command([
+            'git', 'diff-tree', '--name-only', '--no-commit-id', '-r', self.sha,
+            '--', self.absolute_chromium_wpt_dir()
+        ]).splitlines()
+
+        # Remove files on blacklist (MANIFEST.json)
         # TODO(jeffcarp): exclude expectations files
-        # TODO(jeffcarp): exclude manifest files
+        blacklist = ['MANIFEST.json']
+        qualified_blacklist = [WPT_DIR + f for f in blacklist]
+        filtered_files = [f for f in changed_files if f not in qualified_blacklist]
+
+        # Pass those files to format-patch
         return self.host.executive.run_command([
             'git', 'format-patch', '-1', '--stdout',
-            self.sha, self.absolute_chromium_wpt_dir()
-        ])
+            self.sha, '--'
+        ] + filtered_files, cwd=self.absolute_chromium_dir())
 
     @memoized
     def absolute_chromium_wpt_dir(self):
         finder = WebKitFinder(self.host.filesystem)
         return finder.path_from_webkit_base('LayoutTests', 'imported', 'wpt')
+
+    @memoized
+    def absolute_chromium_dir(self):
+        finder = WebKitFinder(self.host.filesystem)
+        return finder.chromium_base()