Moved the GainControlForNewAGC class to a separate file.

webrtc/modules/audio_processing/audio_processing_impl_locking_unittest.cc

Index: webrtc/modules/audio_processing/audio_processing_impl_locking_unittest.cc
diff --git a/webrtc/modules/audio_processing/audio_processing_impl_locking_unittest.cc b/webrtc/modules/audio_processing/audio_processing_impl_locking_unittest.cc
index 3d2c71fb2dbef38993eef42054aa2b27db9e6f23..52c5643d2db670fab5bf7516addc5efa4ab23a88 100644
--- a/webrtc/modules/audio_processing/audio_processing_impl_locking_unittest.cc
+++ b/webrtc/modules/audio_processing/audio_processing_impl_locking_unittest.cc
@@ -596,7 +596,6 @@ bool StatsProcessor::Process() {
                 (test_config_->aec_type ==
                  AecType::BasicWebRtcAecSettingsWithAecMobile));
   EXPECT_TRUE(apm_->gain_control()->is_enabled());
-  apm_->gain_control()->stream_analog_level();
   EXPECT_TRUE(apm_->noise_suppression()->is_enabled());
 
   // The below return values are not testable.
@@ -709,9 +708,12 @@ void CaptureProcessor::CallApmCaptureSide() {
   // Prepare a proper capture side processing API call input.
   PrepareFrame();
 
-  // Set the stream delay
+  // Set the stream delay.
   apm_->set_stream_delay_ms(30);
 
+  // Set the analog level.
+  apm_->gain_control()->set_stream_analog_level(80);
+
   // Call the specified capture side API processing method.
   int result = AudioProcessing::kNoError;
   switch (test_config_->capture_api_function) {
@@ -734,6 +736,9 @@ void CaptureProcessor::CallApmCaptureSide() {
       FAIL();
   }
 
+  // Retrieve the new analog level.
+  apm_->gain_control()->stream_analog_level();

[the sun, 2016/02/09 11:49:55]

Just for testing? It's a bit confusing that you say "Retrieve analog level" but
never actually do anything with it. EXPECT_EQ(80, apm->...); ?
I first thought you were relying on some side effect to be triggered.

[peah-webrtc, 2016/02/10 09:33:37]

The problem with that is that the purpose is not at all to test the
functionality but rather to hammer the api in order to find deadlocks and for
the thread sanitizers to be able to detect threading problems.. As I have no
idea of what the return value should be, I'd rather just not act on it. 

To test the actual functionality in the AGC I think it is better to test that in
another test that tests the AGC functionality.

Does that make sense?

+
   // Check the return code for error.
   ASSERT_EQ(AudioProcessing::kNoError, result);
 }