Fix the environment for calling git number.

Calling git number requires that that depot tools is on the path so that
git-number can be found and requires the CHROME_HEADLESS environment
variable to be set.

Change-Id: Iabb8ec6732ca2bcc0f3209449e23a7d0a4f629e3
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/tools/depot_tools/+/3314033
Auto-Submit: Garrett Beaty <gbeaty@google.com>
Reviewed-by: Gavin Mak <gavinmak@google.com>
Commit-Queue: Gavin Mak <gavinmak@google.com>

recipes/README.recipes.md

@@ -375,7 +375,7 @@ Returns:
       https://gerrit-review.googlesource.com/Documentation/rest-api-changes.html#submit-change
 ### *recipe_modules* / [git](/recipes/recipe_modules/git)
 
-[DEPS](/recipes/recipe_modules/git/__init__.py#3): [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/raw\_io][recipe_engine/recipe_modules/raw_io], [recipe\_engine/runtime][recipe_engine/recipe_modules/runtime], [recipe\_engine/step][recipe_engine/recipe_modules/step]
+[DEPS](/recipes/recipe_modules/git/__init__.py#3): [depot\_tools](#recipe_modules-depot_tools), [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/raw\_io][recipe_engine/recipe_modules/raw_io], [recipe\_engine/runtime][recipe_engine/recipe_modules/runtime], [recipe\_engine/step][recipe_engine/recipe_modules/step]
 
 PYTHON_VERSION_COMPATIBILITY: PY2+3
 

recipes/recipe_modules/git/__init__.py

 PYTHON_VERSION_COMPATIBILITY = 'PY2+3'
 
 DEPS = [
+  'depot_tools',
   'recipe_engine/buildbucket',
   'recipe_engine/context',
   'recipe_engine/runtime',

recipes/recipe_modules/git/api.py

@@ -451,7 +451,12 @@ class GitApi(recipe_api.RecipeApi):
 
     args = ['number']
     args.extend(commitrefs or [])
-    step_result = self(*args,
-                       stdout=self.m.raw_io.output_text(add_output_log=True),
-                       step_test_data=step_test_data)
+    # Put depot_tools on the path so that git-number can be found
+    with self.m.depot_tools.on_path():
+      # git-number is only meant for use on bots, so it prints an error message
+      # if CHROME_HEADLESS is not set
+      with self.m.context(env={'CHROME_HEADLESS': '1'}):
+        step_result = self(*args,
+                          stdout=self.m.raw_io.output_text(add_output_log=True),
+                          step_test_data=step_test_data)
     return [l.strip() for l in step_result.stdout.strip().splitlines()]