Use an explicit identifier in Config

This let's us use them to configure them when using WebRTC as an external library. One use case where this is necessary is in the Android OS.

Review URL: https://codereview.webrtc.org/1538643004

Cr-Commit-Position: refs/heads/master@{#11231}

talk/libjingle.gyp

@@ -712,10 +712,16 @@
       'include_dirs': [
         '<(DEPTH)/testing/gtest/include',
       ],
+      'include_dirs!': [
+        '<(DEPTH)/webrtc',
+      ],
       'direct_dependent_settings': {
         'include_dirs': [
           '<(DEPTH)/testing/gtest/include',
         ],
+        'include_dirs!': [
+          '<(DEPTH)/webrtc',
+        ],
       },
       'sources': [
         'session/media/audiomonitor.cc',

webrtc/BUILD.gn

@@ -238,6 +238,12 @@ source_set("webrtc_common") {
 
   configs += [ ":common_config" ]
   public_configs = [ ":common_inherited_config" ]
+
+  if (is_clang) {
+    # Suppress warnings from Chrome's Clang plugins.
+    # See http://code.google.com/p/webrtc/issues/detail?id=163 for details.
+    configs -= [ "//build/config/clang:find_bad_constructs" ]
+  }
 }
 
 source_set("gtest_prod") {

webrtc/common.h

@@ -17,6 +17,23 @@
 
 namespace webrtc {
 
+// Only add new values to the end of the enumeration and never remove (only
+// deprecate) to maintain binary compatibility.
+enum class ConfigOptionID {
+  kMyExperimentForTest,
+  kAlgo1CostFunctionForTest,
+  kTemporalLayersFactory,
+  kNetEqCapacityConfig,
+  kNetEqFastAccelerate,
+  kVoicePacing,
+  kExtendedFilter,
+  kDelayAgnostic,
+  kExperimentalAgc,
+  kExperimentalNs,
+  kBeamforming,
+  kIntelligibility
+};
+
 // Class Config is designed to ease passing a set of options across webrtc code.
 // Options are identified by typename in order to avoid incorrect casts.
 //
@@ -61,8 +78,6 @@ class Config {
   }
 
  private:
-  typedef void* OptionIdentifier;
-
   struct BaseOption {
     virtual ~BaseOption() {}
   };
@@ -76,11 +91,9 @@ class Config {
     T* value;
   };
 
-  // Own implementation of rtti-subset to avoid depending on rtti and its costs.
   template<typename T>
-  static OptionIdentifier identifier() {
-    static char id_placeholder;
-    return &id_placeholder;
+  static ConfigOptionID identifier() {
+    return T::identifier;
   }
 
   // Used to instantiate a default constructed object that doesn't needs to be
@@ -92,7 +105,7 @@ class Config {
     return def;
   }
 
-  typedef std::map<OptionIdentifier, BaseOption*> OptionMap;
+  typedef std::map<ConfigOptionID, BaseOption*> OptionMap;
   OptionMap options_;
 
   // RTC_DISALLOW_COPY_AND_ASSIGN

webrtc/config.h

@@ -16,6 +16,7 @@
 #include <string>
 #include <vector>
 
+#include "webrtc/common.h"
 #include "webrtc/common_types.h"
 #include "webrtc/typedefs.h"
 
@@ -128,6 +129,7 @@ struct VideoEncoderConfig {
 struct NetEqCapacityConfig {
   NetEqCapacityConfig() : enabled(false), capacity(0) {}
   explicit NetEqCapacityConfig(int value) : enabled(true), capacity(value) {}
+  static const ConfigOptionID identifier = ConfigOptionID::kNetEqCapacityConfig;
   bool enabled;
   int capacity;
 };
@@ -135,12 +137,14 @@ struct NetEqCapacityConfig {
 struct NetEqFastAccelerate {
   NetEqFastAccelerate() : enabled(false) {}
   explicit NetEqFastAccelerate(bool value) : enabled(value) {}
+  static const ConfigOptionID identifier = ConfigOptionID::kNetEqFastAccelerate;
   bool enabled;
 };
 
 struct VoicePacing {
   VoicePacing() : enabled(false) {}
   explicit VoicePacing(bool value) : enabled(value) {}
+  static const ConfigOptionID identifier = ConfigOptionID::kVoicePacing;
   bool enabled;
 };
 

webrtc/modules/audio_processing/include/audio_processing.h

@@ -65,6 +65,7 @@ class VoiceDetection;
 struct ExtendedFilter {
   ExtendedFilter() : enabled(false) {}
   explicit ExtendedFilter(bool enabled) : enabled(enabled) {}
+  static const ConfigOptionID identifier = ConfigOptionID::kExtendedFilter;
   bool enabled;
 };
 
@@ -76,6 +77,7 @@ struct ExtendedFilter {
 struct DelayAgnostic {
   DelayAgnostic() : enabled(false) {}
   explicit DelayAgnostic(bool enabled) : enabled(enabled) {}
+  static const ConfigOptionID identifier = ConfigOptionID::kDelayAgnostic;
   bool enabled;
 };
 
@@ -96,6 +98,7 @@ struct ExperimentalAgc {
       : enabled(enabled), startup_min_volume(kAgcStartupMinVolume) {}
   ExperimentalAgc(bool enabled, int startup_min_volume)
       : enabled(enabled), startup_min_volume(startup_min_volume) {}
+  static const ConfigOptionID identifier = ConfigOptionID::kExperimentalAgc;
   bool enabled;
   int startup_min_volume;
 };
@@ -105,6 +108,7 @@ struct ExperimentalAgc {
 struct ExperimentalNs {
   ExperimentalNs() : enabled(false) {}
   explicit ExperimentalNs(bool enabled) : enabled(enabled) {}
+  static const ConfigOptionID identifier = ConfigOptionID::kExperimentalNs;
   bool enabled;
 };
 
@@ -127,6 +131,7 @@ struct Beamforming {
       : enabled(enabled),
         array_geometry(array_geometry),
         target_direction(target_direction) {}
+  static const ConfigOptionID identifier = ConfigOptionID::kBeamforming;
   const bool enabled;
   const std::vector<Point> array_geometry;
   const SphericalPointf target_direction;
@@ -141,6 +146,7 @@ struct Beamforming {
 struct Intelligibility {
   Intelligibility() : enabled(false) {}
   explicit Intelligibility(bool enabled) : enabled(enabled) {}
+  static const ConfigOptionID identifier = ConfigOptionID::kIntelligibility;
   bool enabled;
 };
 

webrtc/modules/video_coding/codecs/vp8/temporal_layers.h

@@ -14,6 +14,7 @@
 
 #include "vpx/vpx_encoder.h"
 
+#include "webrtc/common.h"
 #include "webrtc/common_video/include/video_image.h"
 #include "webrtc/typedefs.h"
 
@@ -30,6 +31,8 @@ class TemporalLayers {
     virtual ~Factory() {}
     virtual TemporalLayers* Create(int temporal_layers,
                                    uint8_t initial_tl0_pic_idx) const;
+    static const ConfigOptionID identifier =
+        ConfigOptionID::kTemporalLayersFactory;
   };
 
   virtual ~TemporalLayers() {}

webrtc/test/common_unittest.cc

@@ -15,6 +15,7 @@ namespace webrtc {
 namespace {
 
 struct MyExperiment {
+  static const ConfigOptionID identifier = ConfigOptionID::kMyExperimentForTest;
   static const int kDefaultFactor;
   static const int kDefaultOffset;
 
@@ -56,6 +57,8 @@ TEST(Config, SetNullSetsTheOptionBackToDefault) {
 }
 
 struct Algo1_CostFunction {
+  static const ConfigOptionID identifier =
+      ConfigOptionID::kAlgo1CostFunctionForTest;
   Algo1_CostFunction() {}
 
   virtual int cost(int x) const {