Fix invalid casts from ComplexFeature to SimpleFeature.

tools/json_schema_compiler/test/features_generation_unittest.cc

 // Copyright 2016 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "extensions/common/features/api_feature.h"
 #include "extensions/common/features/complex_feature.h"
 #include "extensions/common/features/feature.h"
 #include "extensions/common/features/simple_feature.h"
 #include "testing/gtest/include/gtest/gtest.h"
 #include "tools/json_schema_compiler/test/features_compiler_test.h"
@@ skipping 269 matching lines @@
   {
     APIFeature* feature = GetAPIFeature("alias_source");
     FeatureComparator comparator("alias_source");
     comparator.contexts = {Feature::BLESSED_EXTENSION_CONTEXT};
     comparator.channel.reset(
         new version_info::Channel(version_info::Channel::STABLE));
     comparator.alias = "alias";
     comparator.CompareFeature(feature);
   }
   {
-    Feature* feature = GetAPIFeature("complex_alias");
+    Feature* feature = provider.GetFeature("complex_alias");
     ASSERT_EQ("", feature->alias());
     ASSERT_EQ("complex_alias_source", feature->source());
   }
   {
-    Feature* feature = GetAPIFeature("complex_alias_source");
+    Feature* feature = provider.GetFeature("complex_alias_source");
     ASSERT_EQ("complex_alias", feature->alias());
     ASSERT_EQ("", feature->source());
   }
   {
     Feature* feature = GetAPIFeature("parent_source");
     ASSERT_EQ("parent_source_alias", feature->alias());
     ASSERT_EQ("", feature->source());
   }
   {
     Feature* feature = GetAPIFeature("parent_source.child");
@@ skipping 11 matching lines @@
     ASSERT_EQ("", feature->source());
   }
   {
     Feature* feature = GetAPIFeature("alias_parent.child");
     ASSERT_EQ("", feature->alias());
     ASSERT_EQ("child_source", feature->source());
   }
 }
 
 }  // namespace extensions