diff --git a/DEPS b/DEPS
index dca84f6f7be..5c8057caef9 100644
--- a/DEPS
+++ b/DEPS
@@ -19,7 +19,7 @@
 
 vars = {
   'chromium_git': 'https://chromium.googlesource.com',
-  'mojo_sdk_revision': '487fee0efc6b6792f26a62b39ac010696bbb18bb',
+  'mojo_sdk_revision': '8622a959b150022f5abfc84f7a4acd19eda0150b',
   'mojo_devtools_revision': '49879d78ce4486e10c2214a101d9b2e82794b2f4',
   'skia_revision': '0d39d37ddcfb3847795639eaef513f1112eba627',
 
diff --git a/engine/src/flutter/sky/tools/roll/patch.py b/engine/src/flutter/sky/tools/roll/patch.py
index 5168dac36e0..fbc2389e26c 100755
--- a/engine/src/flutter/sky/tools/roll/patch.py
+++ b/engine/src/flutter/sky/tools/roll/patch.py
@@ -14,10 +14,6 @@ def patch_and_filter(dest_dir, relative_patches_dir):
       lambda line: not "gyp_environment" in line)
   utils.commit("filter gyp_environment out of build/landmines.py")
 
-  utils.filter_file("mojo/dart/embedder/BUILD.gn",
-      lambda line: not "tonic" in line)
-  utils.commit("filter tonic out of mojo/dart/embedder/BUILD.gn")
-
   patch(dest_dir, relative_patches_dir)
 
 
diff --git a/engine/src/flutter/sky/tools/roll/roll.py b/engine/src/flutter/sky/tools/roll/roll.py
index 4eea4a28876..18f2f0a4a05 100755
--- a/engine/src/flutter/sky/tools/roll/roll.py
+++ b/engine/src/flutter/sky/tools/roll/roll.py
@@ -74,7 +74,8 @@ dirs_from_mojo = [
     'mojo/application',
     'mojo/common',
     'mojo/converters',
-    'mojo/dart/embedder',
+    ('mojo/dart/embedder', ['embedder.gni']),
+    'mojo/dart/observatory',
     'mojo/data_pipe_utils',
     'mojo/edk',
     'mojo/environment',
@@ -102,15 +103,25 @@ files_not_to_roll = [
 
 
 def rev(source_dir, dest_dir, dirs_to_rev, name):
-    for d in dirs_to_rev:
+    for dir_to_rev in dirs_to_rev:
+      if type(dir_to_rev) is tuple:
+          d, file_subset = dir_to_rev
+      else:
+          d = dir_to_rev
+          file_subset = None
       print "removing directory %s" % d
       try:
           system(["git", "rm", "-r", d], cwd=dest_dir)
       except subprocess.CalledProcessError:
           print "Could not remove %s" % d
       print "cloning directory %s" % d
-      files = system(["git", "ls-files", d], cwd=source_dir)
-      for f in files.splitlines():
+
+      if file_subset is None:
+          files = system(["git", "ls-files", d], cwd=source_dir).splitlines()
+      else:
+          files = [os.path.join(d, f) for f in file_subset]
+
+      for f in files:
           source_path = os.path.join(source_dir, f)
           if not os.path.isfile(source_path):
               continue