Reduce size of generated extension FeatureProviders.

extensions/common/features/simple_feature.h

 // Copyright 2014 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.
 
 #ifndef EXTENSIONS_COMMON_FEATURES_SIMPLE_FEATURE_H_
 #define EXTENSIONS_COMMON_FEATURES_SIMPLE_FEATURE_H_
 
 #include <stddef.h>
 
+#include <initializer_list>
 #include <memory>
 #include <set>
 #include <string>
 #include <vector>
 
 #include "base/callback_forward.h"
 #include "base/gtest_prod_util.h"
 #include "base/lazy_instance.h"
 #include "base/macros.h"
 #include "base/values.h"
@@ skipping 77 matching lines @@
     EXTERNAL_COMPONENT_LOCATION,
     POLICY_LOCATION,
   };
 
   // Setters used by generated code to create the feature.
   // NOTE: These setters use rvalue references deliberately. These should only
   // ever be used by generated code, and we ensure that in each call, the new
   // value is constructed in-place. This allows us to avoid a copy when we
   // assign it to the value in this class, and results in noticable improvements
   // in both speed and binary size.
-  void set_blacklist(std::vector<std::string>&& blacklist);
+  // TODO(dcheng): Not sure why this needs a style exception, we can still move
+  // when we pass by value? Perhaps codegen is still worse.

[Devlin, 2016/07/27 15:36:49]

Passing by rvalue reference reduced binary size and had the intentional side
effect of discouraging use of these functions when it would cause a copy.

+  void set_blacklist(std::initializer_list<const char* const> blacklist);
   void set_channel(version_info::Channel channel) {
     channel_.reset(new version_info::Channel(channel));
   }
   void set_command_line_switch(std::string&& command_line_switch);

[dcheng, 2016/07/27 09:48:50]

This is the last thing that passes by rvalue: what do you think of just making
this consistent with set_name and passing by StringPiece?

[Devlin, 2016/07/27 16:43:59]

Sure.  Any reason not to?

[dcheng, 2016/07/27 17:02:36]

Done.

   void set_component_extensions_auto_granted(bool granted) {
     component_extensions_auto_granted_ = granted;
   }
-  void set_contexts(std::vector<Context>&& contexts);
-  void set_dependencies(std::vector<std::string>&& dependencies);
-  void set_extension_types(std::vector<Manifest::Type>&& types);
+  void set_contexts(std::initializer_list<Context> contexts);
+  void set_dependencies(std::initializer_list<const char* const> dependencies);
+  void set_extension_types(std::initializer_list<Manifest::Type> types);
   void set_internal(bool is_internal) { is_internal_ = is_internal; }
   void set_location(Location location) { location_ = location; }
   // set_matches() is an exception to pass-by-value since we construct an
   // URLPatternSet from the vector of strings.
   // TODO(devlin): Pass in an URLPatternSet directly.
-  void set_matches(const std::vector<std::string>& matches);
+  void set_matches(std::initializer_list<const char* const> matches);
   void set_max_manifest_version(int max_manifest_version) {
     max_manifest_version_ = max_manifest_version;
   }
   void set_min_manifest_version(int min_manifest_version) {
     min_manifest_version_ = min_manifest_version;
   }
   void set_noparent(bool no_parent) { no_parent_ = no_parent; }
-  void set_platforms(std::vector<Platform>&& platforms);
-  void set_whitelist(std::vector<std::string>&& whitelist);
+  void set_platforms(std::initializer_list<Platform> platforms);
+  void set_whitelist(std::initializer_list<const char* const> whitelist);
 
  protected:
   // Accessors used by subclasses in feature verification.
   const std::vector<std::string>& blacklist() const { return blacklist_; }
   const std::vector<std::string>& whitelist() const { return whitelist_; }
   const std::vector<Manifest::Type>& extension_types() const {
     return extension_types_;
   }
   const std::vector<Platform>& platforms() const { return platforms_; }
   const std::vector<Context>& contexts() const { return contexts_; }
@@ skipping 89 matching lines @@
   bool is_internal_;
   std::string command_line_switch_;
   std::unique_ptr<version_info::Channel> channel_;
 
   DISALLOW_COPY_AND_ASSIGN(SimpleFeature);
 };
 
 }  // namespace extensions
 
 #endif  // EXTENSIONS_COMMON_FEATURES_SIMPLE_FEATURE_H_