Stop to use contextmanager for goma.build_with_goma

scripts/slave/recipe_modules/chromium/api.py

Index: scripts/slave/recipe_modules/chromium/api.py
diff --git a/scripts/slave/recipe_modules/chromium/api.py b/scripts/slave/recipe_modules/chromium/api.py
index eed50545ce7a30f2a7fb17f8f88afcacc2c52f31..b1b22092395e854199ec4c984d25573582c88769 100644
--- a/scripts/slave/recipe_modules/chromium/api.py
+++ b/scripts/slave/recipe_modules/chromium/api.py
@@ -279,37 +279,30 @@ class ChromiumApi(recipe_api.RecipeApi):
       if self.c.compile_py.build_args:
         command.extend(self.c.compile_py.build_args)
 
-      if use_goma_module:
-        # Set -j just before 'with self.m.goma.build_with_goma('
-        # for ninja_log_command being set correctly if starting goma
-        # fails.
-        command += ['-j', self.m.goma.recommended_goma_jobs]
-
       if targets is not None:
         # Add build targets to command ('All', 'chrome' etc).
         command += targets
 
       kwargs.pop('env', {})
 
-      # TODO(tikuta): Set disable_local_fallback option appropriately.
       if use_goma_module:
         with self.m.goma.build_with_goma(
             env=goma_env,
             ninja_log_outdir=target_output_dir,
             ninja_log_compiler=self.c.compile_py.compiler or 'goma',
-            ninja_log_command=command,
-            allow_build_without_goma=allow_build_without_goma):
-          if 'GOMA_DISABLED' in goma_env:
-            self.m.goma.remove_j_flag(command)
-            ninja_env['GOMA_DISABLED'] = 'true'
-            if self.m.platform.is_win:
-              self.m.python('update windows env',
-                            script=self.package_repo_resource(
-                                'scripts', 'slave', 'update_windows_env.py'),
-                            args=['--envfile-dir', str(target_output_dir)],
-                            env=goma_env)
+            ninja_command=command,
+            allow_build_without_goma=allow_build_without_goma) as (
+                env_update, ninja_command):
+          ninja_env.update(env_update)
+          if self.m.platform.is_win and len(env_update) > 0:
+            goma_env.update(env_update)
+            self.m.python('update windows env',
+                          script=self.package_repo_resource(
+                              'scripts', 'slave', 'update_windows_env.py'),
+                          args=['--envfile-dir', str(target_output_dir)],
+                          env=goma_env)
           self.m.step(name or 'compile with ninja',
-                      command,
+                      ninja_command,
                       env=ninja_env,
                       **kwargs)
       else: