Reland of added functionality for specifying the initial signal level to use for the gain estimation

webrtc/modules/audio_processing/audio_processing_impl.h

Index: webrtc/modules/audio_processing/audio_processing_impl.h
diff --git a/webrtc/modules/audio_processing/audio_processing_impl.h b/webrtc/modules/audio_processing/audio_processing_impl.h
index c8162c1b66dcecf314997c461a6765745d163fce..be0e9518c38a06fecad89c0b9073f1451f3310a6 100644
--- a/webrtc/modules/audio_processing/audio_processing_impl.h
+++ b/webrtc/modules/audio_processing/audio_processing_impl.h
@@ -17,6 +17,7 @@
 #include <vector>
 
 #include "webrtc/base/criticalsection.h"
+#include "webrtc/base/gtest_prod_util.h"
 #include "webrtc/base/ignore_wundef.h"
 #include "webrtc/base/thread_annotations.h"
 #include "webrtc/modules/audio_processing/audio_buffer.h"
@@ -132,6 +133,11 @@ class AudioProcessingImpl : public AudioProcessing {
       EXCLUSIVE_LOCKS_REQUIRED(crit_render_, crit_capture_);
 
  private:
+  // TODO(peah): These friend classes should be removed as soon as the new
+  // parameter setting scheme allows.
+  FRIEND_TEST_ALL_PREFIXES(ApmConfiguration, DefaultBehavior);
+  FRIEND_TEST_ALL_PREFIXES(ApmConfiguration, ValidConfigBehavior);
+  FRIEND_TEST_ALL_PREFIXES(ApmConfiguration, InValidConfigBehavior);
   struct ApmPublicSubmodules;
   struct ApmPrivateSubmodules;
 
@@ -269,6 +275,9 @@ class AudioProcessingImpl : public AudioProcessing {
   rtc::CriticalSection crit_render_ ACQUIRED_BEFORE(crit_capture_);
   rtc::CriticalSection crit_capture_;
 
+  // Struct containing the Config specifying the behavior of APM.
+  AudioProcessing::Config config_;
+
   // Class containing information about what submodules are active.
   ApmSubmoduleStates submodule_states_;