diff --git a/tools_webrtc/autoroller/roll_deps.py b/tools_webrtc/autoroller/roll_deps.py
index 66e5977853..11e1fb8cff 100755
--- a/tools_webrtc/autoroller/roll_deps.py
+++ b/tools_webrtc/autoroller/roll_deps.py
@@ -234,18 +234,13 @@ def BuildDepsentryDict(deps_dict):
   return result
 
 
-def _RemoveStringPrefix(string, substring):
-  assert string.startswith(substring)
-  return string[len(substring):]
-
-
 def _FindChangedCipdPackages(path, old_pkgs, new_pkgs):
   assert ({p['package'] for p in old_pkgs} ==
           {p['package'] for p in new_pkgs})
   for old_pkg in old_pkgs:
     for new_pkg in new_pkgs:
-      old_version = _RemoveStringPrefix(old_pkg['version'], 'version:')
-      new_version = _RemoveStringPrefix(new_pkg['version'], 'version:')
+      old_version = old_pkg['version']
+      new_version = new_pkg['version']
       if (old_pkg['package'] == new_pkg['package'] and
           old_version != new_version):
         logging.debug('Roll dependency %s to %s', path, new_version)
@@ -289,10 +284,14 @@ def CalculateChangedDeps(webrtc_deps, new_cr_deps):
           'WebRTC DEPS entry %s has a different URL (%s) than Chromium (%s).' %
           (path, webrtc_deps_entry.url, cr_deps_entry.url))
     else:
-      # Use the HEAD of the deps repo.
-      stdout, _ = _RunCommand(['git', 'ls-remote', webrtc_deps_entry.url,
-                               'HEAD'])
-      new_rev = stdout.strip().split('\t')[0]
+      if isinstance(webrtc_deps_entry, DepsEntry):
+        # Use the HEAD of the deps repo.
+        stdout, _ = _RunCommand(['git', 'ls-remote', webrtc_deps_entry.url,
+                                'HEAD'])
+        new_rev = stdout.strip().split('\t')[0]
+      else:
+        raise RollError('WebRTC DEPS entry %s is missing from Chromium. Remove '
+                        'it or add it to DONT_AUTOROLL_THESE.' % path)
 
     # Check if an update is necessary.
     if webrtc_deps_entry.revision != new_rev:
@@ -395,7 +394,8 @@ def UpdateDepsFile(deps_filename, rev_update, changed_deps):
           'target_os = ["android", "unix", "mac", "ios", "win"];\n'
           'Then run "gclient sync" again.' % local_dep_dir)
     if isinstance(dep, ChangedCipdPackage):
-      update = '%s:%s@%s' % (dep.path, dep.package, dep.new_version)
+      package = dep.package.format()  # Eliminate double curly brackets
+      update = '%s:%s@%s' % (dep.path, package, dep.new_version)
     else:
       update = '%s@%s' % (dep.path, dep.new_rev)
     _RunCommand(['gclient', 'setdep', '--revision', update],
diff --git a/tools_webrtc/autoroller/unittests/roll_deps_test.py b/tools_webrtc/autoroller/unittests/roll_deps_test.py
index c8d22f2e72..2c19198aae 100755
--- a/tools_webrtc/autoroller/unittests/roll_deps_test.py
+++ b/tools_webrtc/autoroller/unittests/roll_deps_test.py
@@ -144,8 +144,8 @@ class TestRollChromiumRevision(unittest.TestCase):
 
     self.assertEquals(changed_deps[2].path, 'src/third_party/xstream')
     self.assertEquals(changed_deps[2].package, 'chromium/third_party/xstream')
-    self.assertEquals(changed_deps[2].current_version, '1.4.8-cr0')
-    self.assertEquals(changed_deps[2].new_version, '1.10.0-cr0')
+    self.assertEquals(changed_deps[2].current_version, 'version:1.4.8-cr0')
+    self.assertEquals(changed_deps[2].new_version, 'version:1.10.0-cr0')
 
 
 class TestChooseCQMode(unittest.TestCase):