Reland "Correct AEC3 multichannel functionality activation"

This is a reland of 9dda1b3a484ebeef921e419406402039f3852427

Original change's description:
> Correct AEC3 multichannel functionality activation
> 
> This CL corrects the AEC3 multichannel activation
> to also work for the case when a factory is used
> for the activation.
> 
> Bug: webrtc:10913
> Change-Id: Ic2807d8bcef759261fde14447cff30633ba248dc
> Reviewed-on: https://webrtc-review.googlesource.com/c/src/+/158794
> Commit-Queue: Per Åhgren <peah@webrtc.org>
> Reviewed-by: Sam Zackrisson <saza@webrtc.org>
> Cr-Commit-Position: refs/heads/master@{#29676}

Bug: webrtc:10913
Change-Id: Ibfe4e8a51183390a4054514bb294c89c2ea201e9
Reviewed-on: https://webrtc-review.googlesource.com/c/src/+/158880
Reviewed-by: Sam Zackrisson <saza@webrtc.org>
Commit-Queue: Per Åhgren <peah@webrtc.org>
Cr-Commit-Position: refs/heads/master@{#29685}

api/audio/echo_canceller3_factory.cc

@@ -21,9 +21,16 @@ EchoCanceller3Factory::EchoCanceller3Factory(const EchoCanceller3Config& config)
     : config_(config) {}
 
 std::unique_ptr<EchoControl> EchoCanceller3Factory::Create(int sample_rate_hz) {
-  return std::make_unique<EchoCanceller3>(config_, sample_rate_hz,
-                                          /*num_render_channels=*/1,
+  return Create(sample_rate_hz, /*num_render_channels=*/1,
                 /*num_capture_channels=*/1);
 }
 
+std::unique_ptr<EchoControl> EchoCanceller3Factory::Create(
+    int sample_rate_hz,
+    int num_render_channels,
+    int num_capture_channels) {
+  return std::make_unique<EchoCanceller3>(
+      config_, sample_rate_hz, num_render_channels, num_capture_channels);
+}
+
 }  // namespace webrtc

api/audio/echo_canceller3_factory.h

@@ -29,9 +29,15 @@ class RTC_EXPORT EchoCanceller3Factory : public EchoControlFactory {
   explicit EchoCanceller3Factory(const EchoCanceller3Config& config);
 
   // Creates an EchoCanceller3 running at the specified sampling rate using a
-  // mono setup
+  // mono setup.
   std::unique_ptr<EchoControl> Create(int sample_rate_hz) override;
 
+  // Creates an EchoCanceller3 running at the specified sampling rate using a
+  // multichannel setup.
+  std::unique_ptr<EchoControl> Create(int sample_rate_hz,
+                                      int num_render_channels,
+                                      int num_capture_channels) override;
+
  private:
   const EchoCanceller3Config config_;
 };

api/audio/echo_control.h

@@ -51,6 +51,13 @@ class EchoControl {
 class EchoControlFactory {
  public:
   virtual std::unique_ptr<EchoControl> Create(int sample_rate_hz) = 0;
+  // TODO(peah): Make pure virtual.
+  virtual std::unique_ptr<EchoControl> Create(int sample_rate_hz,
+                                              int num_render_channels,
+                                              int num_capture_channels) {
+    return nullptr;
+  }
+
   virtual ~EchoControlFactory() = default;
 };
 }  // namespace webrtc

modules/audio_processing/audio_processing_impl.cc

@@ -1783,8 +1783,8 @@ void AudioProcessingImpl::InitializeEchoController() {
   if (use_echo_controller) {
     // Create and activate the echo controller.
     if (echo_control_factory_) {
-      submodules_.echo_controller =
-          echo_control_factory_->Create(proc_sample_rate_hz());
+      submodules_.echo_controller = echo_control_factory_->Create(
+          proc_sample_rate_hz(), num_reverse_channels(), num_proc_channels());
     } else {
       submodules_.echo_controller = std::make_unique<EchoCanceller3>(
           EchoCanceller3Config(), proc_sample_rate_hz(), num_reverse_channels(),

modules/audio_processing/audio_processing_impl_unittest.cc

@@ -54,6 +54,12 @@ class MockEchoControlFactory : public EchoControlFactory {
   // Returns a pointer to the next MockEchoControl that this factory creates.
   MockEchoControl* GetNext() const { return next_mock_.get(); }
   std::unique_ptr<EchoControl> Create(int sample_rate_hz) override {
+    RTC_NOTREACHED();
+    return nullptr;
+  }
+  std::unique_ptr<EchoControl> Create(int sample_rate_hz,
+                                      int num_render_channels,
+                                      int num_capture_channels) override {
     std::unique_ptr<EchoControl> mock = std::move(next_mock_);
     next_mock_ = std::make_unique<MockEchoControl>();
     return mock;

modules/audio_processing/audio_processing_unittest.cc

@@ -2430,8 +2430,8 @@ class MyEchoControlFactory : public EchoControlFactory {
   }
 
   std::unique_ptr<EchoControl> Create(int sample_rate_hz,
-                                      size_t num_render_channels,
-                                      size_t num_capture_channels) {
+                                      int num_render_channels,
+                                      int num_capture_channels) {
     return Create(sample_rate_hz);
   }
 };