Pull in mojo/devtools via DEPS

DEPS

@@ -20,6 +20,7 @@
 vars = {
   'chromium_git': 'https://chromium.googlesource.com',
   'mojo_sdk_revision': '76ff57433b48527dc491dac4c52c9d71a7c3a0e3',
+  'mojo_devtools_revision': '2feda37728d3e551ef543b8f6c4f4b20eaa2d81f',
   'skia_revision': '29ccdf86ab0a1649fd775c9431891bacb1391e99',
   'dart_revision': '95c951ad190f156eb61b99203c2e4948211c44a7',
   'dart_observatory_packages_revision': 'cdc4b3d4c15b9c0c8e7702dff127b440afbb7485',
@@ -31,6 +32,7 @@ vars = {
 # If you need to add a new host, contact chrome infrastructure team.
 allowed_hosts = [
   'chromium.googlesource.com',
+  'github.com',
 ]
 
 deps = {
@@ -58,6 +60,10 @@ deps = {
    Var('chromium_git') + '/external/github.com/domokit/mojo_sdk' + '@' +
    Var('mojo_sdk_revision'),
 
+  'src/mojo/devtools':
+   'https://github.com/domokit/devtools.git' + '@' +
+   Var('mojo_devtools_revision'),
+
   'src/third_party/skia':
    Var('chromium_git') + '/skia.git' + '@' +  Var('skia_revision'),
 

engine/src/flutter/.gitignore

@@ -25,6 +25,7 @@ Thumbs.db
 /buildtools/
 /dart/
 /dart-pub-cache/
+/mojo/devtools/
 /mojo/public/
 /native_client/
 /out/