diff --git a/.editorconfig b/.editorconfig
new file mode 100644
index 0000000..2491fdf
--- /dev/null
+++ b/.editorconfig
@@ -0,0 +1,3 @@
+[*.py]
+indent_style = space
+indent_size = 2
diff --git a/.gitignore b/.gitignore
index ae30641..4c20aff 100644
--- a/.gitignore
+++ b/.gitignore
@@ -42,6 +42,7 @@
 .metadata
 .project
 .pydevproject
+.recipe_deps
 .checkstyle
 cscope.*
 out/
@@ -54,7 +55,6 @@
 Thumbs.db
 # Settings directories for eclipse
 /.externalToolBuilders/
-/.recipe_deps/
 /.settings/
 /.vs/
 # Visual Studio Code
diff --git a/infra/README.recipes.md b/infra/README.recipes.md
index 72fb3b3..5c58118 100644
--- a/infra/README.recipes.md
+++ b/infra/README.recipes.md
@@ -8,12 +8,17 @@
 
 ### *recipes* / [gn](/infra/recipes/gn.py)
 
-[DEPS](/infra/recipes/gn.py#6): [recipe\_engine/path][recipe_engine/recipe_modules/path], [recipe\_engine/platform][recipe_engine/recipe_modules/platform], [recipe\_engine/step][recipe_engine/recipe_modules/step]
+[DEPS](/infra/recipes/gn.py#6): [recipe\_engine/buildbucket][recipe_engine/recipe_modules/buildbucket], [recipe\_engine/context][recipe_engine/recipe_modules/context], [recipe\_engine/path][recipe_engine/recipe_modules/path], [recipe\_engine/platform][recipe_engine/recipe_modules/platform], [recipe\_engine/properties][recipe_engine/recipe_modules/properties], [recipe\_engine/python][recipe_engine/recipe_modules/python], [recipe\_engine/step][recipe_engine/recipe_modules/step], [recipe\_engine/url][recipe_engine/recipe_modules/url]
 
 Recipe for building GN.
 
-&mdash; **def [RunSteps](/infra/recipes/gn.py#13)(api):**
+&mdash; **def [RunSteps](/infra/recipes/gn.py#18)(api):**
 
+[recipe_engine/recipe_modules/buildbucket]: https://chromium.googlesource.com/infra/luci/recipes-py.git/+/10f67fe223a7973a95bc5fff219d1a7a3d95a326/README.recipes.md#recipe_modules-buildbucket
+[recipe_engine/recipe_modules/context]: https://chromium.googlesource.com/infra/luci/recipes-py.git/+/10f67fe223a7973a95bc5fff219d1a7a3d95a326/README.recipes.md#recipe_modules-context
 [recipe_engine/recipe_modules/path]: https://chromium.googlesource.com/infra/luci/recipes-py.git/+/10f67fe223a7973a95bc5fff219d1a7a3d95a326/README.recipes.md#recipe_modules-path
 [recipe_engine/recipe_modules/platform]: https://chromium.googlesource.com/infra/luci/recipes-py.git/+/10f67fe223a7973a95bc5fff219d1a7a3d95a326/README.recipes.md#recipe_modules-platform
+[recipe_engine/recipe_modules/properties]: https://chromium.googlesource.com/infra/luci/recipes-py.git/+/10f67fe223a7973a95bc5fff219d1a7a3d95a326/README.recipes.md#recipe_modules-properties
+[recipe_engine/recipe_modules/python]: https://chromium.googlesource.com/infra/luci/recipes-py.git/+/10f67fe223a7973a95bc5fff219d1a7a3d95a326/README.recipes.md#recipe_modules-python
 [recipe_engine/recipe_modules/step]: https://chromium.googlesource.com/infra/luci/recipes-py.git/+/10f67fe223a7973a95bc5fff219d1a7a3d95a326/README.recipes.md#recipe_modules-step
+[recipe_engine/recipe_modules/url]: https://chromium.googlesource.com/infra/luci/recipes-py.git/+/10f67fe223a7973a95bc5fff219d1a7a3d95a326/README.recipes.md#recipe_modules-url
diff --git a/infra/recipes/gn.expected/ci_linux.json b/infra/recipes/gn.expected/ci_linux.json
new file mode 100644
index 0000000..1a01c40
--- /dev/null
+++ b/infra/recipes/gn.expected/ci_linux.json
@@ -0,0 +1,57 @@
+[
+  {
+    "cmd": [],
+    "name": "git"
+  },
+  {
+    "cmd": [
+      "git",
+      "init",
+      "[START_DIR]/gn"
+    ],
+    "cwd": "[START_DIR]/gn",
+    "name": "git.init",
+    "~followup_annotations": [
+      "@@@STEP_NEST_LEVEL@1@@@"
+    ]
+  },
+  {
+    "cmd": [
+      "git",
+      "fetch",
+      "https://gn.googlesource.com/gn",
+      "aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa"
+    ],
+    "cwd": "[START_DIR]/gn",
+    "name": "git.fetch",
+    "~followup_annotations": [
+      "@@@STEP_NEST_LEVEL@1@@@"
+    ]
+  },
+  {
+    "cmd": [
+      "git",
+      "checkout",
+      "FETCH_HEAD"
+    ],
+    "cwd": "[START_DIR]/gn",
+    "name": "git.checkout",
+    "~followup_annotations": [
+      "@@@STEP_NEST_LEVEL@1@@@"
+    ]
+  },
+  {
+    "cmd": [
+      "python",
+      "-u",
+      "[START_DIR]/gn/tools/gn/bootstrap/bootstrap.py",
+      "--no-rebuild"
+    ],
+    "name": "bootstrap"
+  },
+  {
+    "name": "$result",
+    "recipe_result": null,
+    "status_code": 0
+  }
+]
\ No newline at end of file
diff --git a/infra/recipes/gn.expected/ci_mac.json b/infra/recipes/gn.expected/ci_mac.json
new file mode 100644
index 0000000..1a01c40
--- /dev/null
+++ b/infra/recipes/gn.expected/ci_mac.json
@@ -0,0 +1,57 @@
+[
+  {
+    "cmd": [],
+    "name": "git"
+  },
+  {
+    "cmd": [
+      "git",
+      "init",
+      "[START_DIR]/gn"
+    ],
+    "cwd": "[START_DIR]/gn",
+    "name": "git.init",
+    "~followup_annotations": [
+      "@@@STEP_NEST_LEVEL@1@@@"
+    ]
+  },
+  {
+    "cmd": [
+      "git",
+      "fetch",
+      "https://gn.googlesource.com/gn",
+      "aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa"
+    ],
+    "cwd": "[START_DIR]/gn",
+    "name": "git.fetch",
+    "~followup_annotations": [
+      "@@@STEP_NEST_LEVEL@1@@@"
+    ]
+  },
+  {
+    "cmd": [
+      "git",
+      "checkout",
+      "FETCH_HEAD"
+    ],
+    "cwd": "[START_DIR]/gn",
+    "name": "git.checkout",
+    "~followup_annotations": [
+      "@@@STEP_NEST_LEVEL@1@@@"
+    ]
+  },
+  {
+    "cmd": [
+      "python",
+      "-u",
+      "[START_DIR]/gn/tools/gn/bootstrap/bootstrap.py",
+      "--no-rebuild"
+    ],
+    "name": "bootstrap"
+  },
+  {
+    "name": "$result",
+    "recipe_result": null,
+    "status_code": 0
+  }
+]
\ No newline at end of file
diff --git a/infra/recipes/gn.expected/ci_win.json b/infra/recipes/gn.expected/ci_win.json
new file mode 100644
index 0000000..d1fea74
--- /dev/null
+++ b/infra/recipes/gn.expected/ci_win.json
@@ -0,0 +1,57 @@
+[
+  {
+    "cmd": [],
+    "name": "git"
+  },
+  {
+    "cmd": [
+      "git",
+      "init",
+      "[START_DIR]\\gn"
+    ],
+    "cwd": "[START_DIR]\\gn",
+    "name": "git.init",
+    "~followup_annotations": [
+      "@@@STEP_NEST_LEVEL@1@@@"
+    ]
+  },
+  {
+    "cmd": [
+      "git",
+      "fetch",
+      "https://gn.googlesource.com/gn",
+      "aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa"
+    ],
+    "cwd": "[START_DIR]\\gn",
+    "name": "git.fetch",
+    "~followup_annotations": [
+      "@@@STEP_NEST_LEVEL@1@@@"
+    ]
+  },
+  {
+    "cmd": [
+      "git",
+      "checkout",
+      "FETCH_HEAD"
+    ],
+    "cwd": "[START_DIR]\\gn",
+    "name": "git.checkout",
+    "~followup_annotations": [
+      "@@@STEP_NEST_LEVEL@1@@@"
+    ]
+  },
+  {
+    "cmd": [
+      "python",
+      "-u",
+      "[START_DIR]\\gn\\tools\\gn\\bootstrap\\bootstrap.py",
+      "--no-rebuild"
+    ],
+    "name": "bootstrap"
+  },
+  {
+    "name": "$result",
+    "recipe_result": null,
+    "status_code": 0
+  }
+]
\ No newline at end of file
diff --git a/infra/recipes/gn.expected/cq_linux.json b/infra/recipes/gn.expected/cq_linux.json
new file mode 100644
index 0000000..61a5569
--- /dev/null
+++ b/infra/recipes/gn.expected/cq_linux.json
@@ -0,0 +1,57 @@
+[
+  {
+    "cmd": [],
+    "name": "git"
+  },
+  {
+    "cmd": [
+      "git",
+      "init",
+      "[START_DIR]/gn"
+    ],
+    "cwd": "[START_DIR]/gn",
+    "name": "git.init",
+    "~followup_annotations": [
+      "@@@STEP_NEST_LEVEL@1@@@"
+    ]
+  },
+  {
+    "cmd": [
+      "git",
+      "fetch",
+      "https://gn-review.googlesource.com/gn",
+      "refs/changes/00/1000/1"
+    ],
+    "cwd": "[START_DIR]/gn",
+    "name": "git.fetch",
+    "~followup_annotations": [
+      "@@@STEP_NEST_LEVEL@1@@@"
+    ]
+  },
+  {
+    "cmd": [
+      "git",
+      "cherry-pick",
+      "FETCH_HEAD"
+    ],
+    "cwd": "[START_DIR]/gn",
+    "name": "git.cherry-pick",
+    "~followup_annotations": [
+      "@@@STEP_NEST_LEVEL@1@@@"
+    ]
+  },
+  {
+    "cmd": [
+      "python",
+      "-u",
+      "[START_DIR]/gn/tools/gn/bootstrap/bootstrap.py",
+      "--no-rebuild"
+    ],
+    "name": "bootstrap"
+  },
+  {
+    "name": "$result",
+    "recipe_result": null,
+    "status_code": 0
+  }
+]
\ No newline at end of file
diff --git a/infra/recipes/gn.expected/cq_mac.json b/infra/recipes/gn.expected/cq_mac.json
new file mode 100644
index 0000000..61a5569
--- /dev/null
+++ b/infra/recipes/gn.expected/cq_mac.json
@@ -0,0 +1,57 @@
+[
+  {
+    "cmd": [],
+    "name": "git"
+  },
+  {
+    "cmd": [
+      "git",
+      "init",
+      "[START_DIR]/gn"
+    ],
+    "cwd": "[START_DIR]/gn",
+    "name": "git.init",
+    "~followup_annotations": [
+      "@@@STEP_NEST_LEVEL@1@@@"
+    ]
+  },
+  {
+    "cmd": [
+      "git",
+      "fetch",
+      "https://gn-review.googlesource.com/gn",
+      "refs/changes/00/1000/1"
+    ],
+    "cwd": "[START_DIR]/gn",
+    "name": "git.fetch",
+    "~followup_annotations": [
+      "@@@STEP_NEST_LEVEL@1@@@"
+    ]
+  },
+  {
+    "cmd": [
+      "git",
+      "cherry-pick",
+      "FETCH_HEAD"
+    ],
+    "cwd": "[START_DIR]/gn",
+    "name": "git.cherry-pick",
+    "~followup_annotations": [
+      "@@@STEP_NEST_LEVEL@1@@@"
+    ]
+  },
+  {
+    "cmd": [
+      "python",
+      "-u",
+      "[START_DIR]/gn/tools/gn/bootstrap/bootstrap.py",
+      "--no-rebuild"
+    ],
+    "name": "bootstrap"
+  },
+  {
+    "name": "$result",
+    "recipe_result": null,
+    "status_code": 0
+  }
+]
\ No newline at end of file
diff --git a/infra/recipes/gn.expected/cq_win.json b/infra/recipes/gn.expected/cq_win.json
new file mode 100644
index 0000000..11f3933
--- /dev/null
+++ b/infra/recipes/gn.expected/cq_win.json
@@ -0,0 +1,57 @@
+[
+  {
+    "cmd": [],
+    "name": "git"
+  },
+  {
+    "cmd": [
+      "git",
+      "init",
+      "[START_DIR]\\gn"
+    ],
+    "cwd": "[START_DIR]\\gn",
+    "name": "git.init",
+    "~followup_annotations": [
+      "@@@STEP_NEST_LEVEL@1@@@"
+    ]
+  },
+  {
+    "cmd": [
+      "git",
+      "fetch",
+      "https://gn-review.googlesource.com/gn",
+      "refs/changes/00/1000/1"
+    ],
+    "cwd": "[START_DIR]\\gn",
+    "name": "git.fetch",
+    "~followup_annotations": [
+      "@@@STEP_NEST_LEVEL@1@@@"
+    ]
+  },
+  {
+    "cmd": [
+      "git",
+      "cherry-pick",
+      "FETCH_HEAD"
+    ],
+    "cwd": "[START_DIR]\\gn",
+    "name": "git.cherry-pick",
+    "~followup_annotations": [
+      "@@@STEP_NEST_LEVEL@1@@@"
+    ]
+  },
+  {
+    "cmd": [
+      "python",
+      "-u",
+      "[START_DIR]\\gn\\tools\\gn\\bootstrap\\bootstrap.py",
+      "--no-rebuild"
+    ],
+    "name": "bootstrap"
+  },
+  {
+    "name": "$result",
+    "recipe_result": null,
+    "status_code": 0
+  }
+]
\ No newline at end of file
diff --git a/infra/recipes/gn.expected/linux.json b/infra/recipes/gn.expected/linux.json
deleted file mode 100644
index 6631ad0..0000000
--- a/infra/recipes/gn.expected/linux.json
+++ /dev/null
@@ -1,16 +0,0 @@
-[
-  {
-    "cmd": [
-      "git",
-      "clone",
-      "https://gn.googlesource.com/gn",
-      "[START_DIR]/gn"
-    ],
-    "name": "checkout"
-  },
-  {
-    "name": "$result",
-    "recipe_result": null,
-    "status_code": 0
-  }
-]
\ No newline at end of file
diff --git a/infra/recipes/gn.expected/mac.json b/infra/recipes/gn.expected/mac.json
deleted file mode 100644
index 6631ad0..0000000
--- a/infra/recipes/gn.expected/mac.json
+++ /dev/null
@@ -1,16 +0,0 @@
-[
-  {
-    "cmd": [
-      "git",
-      "clone",
-      "https://gn.googlesource.com/gn",
-      "[START_DIR]/gn"
-    ],
-    "name": "checkout"
-  },
-  {
-    "name": "$result",
-    "recipe_result": null,
-    "status_code": 0
-  }
-]
\ No newline at end of file
diff --git a/infra/recipes/gn.expected/win.json b/infra/recipes/gn.expected/win.json
deleted file mode 100644
index c3438b0..0000000
--- a/infra/recipes/gn.expected/win.json
+++ /dev/null
@@ -1,16 +0,0 @@
-[
-  {
-    "cmd": [
-      "git",
-      "clone",
-      "https://gn.googlesource.com/gn",
-      "[START_DIR]\\gn"
-    ],
-    "name": "checkout"
-  },
-  {
-    "name": "$result",
-    "recipe_result": null,
-    "status_code": 0
-  }
-]
\ No newline at end of file
diff --git a/infra/recipes/gn.py b/infra/recipes/gn.py
index 7a4224f..cf551a9 100644
--- a/infra/recipes/gn.py
+++ b/infra/recipes/gn.py
@@ -4,18 +4,64 @@
 """Recipe for building GN."""
 
 DEPS = [
+    'recipe_engine/buildbucket',
+    'recipe_engine/context',
     'recipe_engine/path',
     'recipe_engine/platform',
+    'recipe_engine/properties',
+    'recipe_engine/python',
     'recipe_engine/step',
+    'recipe_engine/url',
 ]
 
 
 def RunSteps(api):
   src_dir = api.path['start_dir'].join('gn')
-  api.step('checkout',
-           ['git', 'clone', 'https://gn.googlesource.com/gn', src_dir])
+
+  with api.step.nest('git'), api.context(cwd=src_dir):
+    api.step('init', ['git', 'init', src_dir])
+
+    build_input = api.buildbucket.build_input
+    if build_input.gitiles_commits:
+      commit = build_input.gitiles_commits[0]
+      api.step('fetch', [
+          'git', 'fetch',
+          'https://%s/%s' % (commit.host, commit.project), commit.id
+      ])
+      api.step('checkout', ['git', 'checkout', 'FETCH_HEAD'])
+    if build_input.gerrit_changes:
+      for change in build_input.gerrit_changes:
+        api.step('fetch', [
+            'git', 'fetch',
+            'https://%s/gn' % change.host,
+            'refs/changes/%s/%s/%s' %
+            (str(change.change)[-2:], change.change, change.patchset)
+        ])
+        api.step('cherry-pick', ['git', 'cherry-pick', 'FETCH_HEAD'])
+
+  api.python(
+      'bootstrap',
+      src_dir.join('tools', 'gn', 'bootstrap', 'bootstrap.py'),
+      args=['--no-rebuild'])
 
 
 def GenTests(api):
   for platform in ('linux', 'mac', 'win'):
-    yield api.test(platform) + api.platform.name(platform)
+    yield (api.test('ci_' + platform) + api.platform.name(platform) +
+           api.properties(buildbucket={
+               'build': {
+                   'tags': [
+                       'buildset:commit/gitiles/gn.googlesource.com/gn/+/'
+                       'aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa',
+                   ]
+               }
+           }))
+    yield (
+        api.test('cq_' + platform) + api.platform.name(platform) +
+        api.properties(buildbucket={
+            'build': {
+                'tags': [
+                    'buildset:patch/gerrit/gn-review.googlesource.com/1000/1',
+                ]
+            }
+        }))