Refactor the way that TestApi works so that it is actually useful.

scripts/slave/recipe_modules/android/api.py

Index: scripts/slave/recipe_modules/android/api.py
diff --git a/scripts/slave/recipe_modules/android/api.py b/scripts/slave/recipe_modules/android/api.py
index e47ec0e529d9ecbf2a81d244c7aec26bc86c9e5d..347f6e10febe25650a29c17d487e520fa6a63801 100644
--- a/scripts/slave/recipe_modules/android/api.py
+++ b/scripts/slave/recipe_modules/android/api.py
@@ -46,10 +46,20 @@ class AOSPApi(recipe_api.RecipeApi):
 
     yield self.m.step(
       'calculate trimmed deps',
-      [self.m.path.checkout('android_webview', 'buildbot', 'deps_whitelist.py'),
-       '--method', 'android_build',
-       '--path-to-deps', self.m.path.checkout('DEPS'),
-       self.m.json.output()])
+      [
+        self.m.path.checkout('android_webview', 'buildbot',
+                             'deps_whitelist.py'),
+        '--method', 'android_build',
+        '--path-to-deps', self.m.path.checkout('DEPS'),
+        self.m.json.output()
+      ],
+      mock_fn=lambda: self.test_api.m.json.output({
+        'blacklist': {
+          'src/blacklist/project/1': None,
+          'src/blacklist/project/2': None,
+        }
+      })
+    )
 
     spec = self.m.gclient.make_config('chromium_bare')
     deps_blacklist = self.m.step_history.last_step().json.output['blacklist']