Revert "Remove APM-internal usage of EchoControlMobile"

This reverts commit 2fbb83b16b4c2c1712cbe898ca3ba42d6da3e96f.

Reason for revert: Speculative revert over failing Chromium bot:
https://ci.chromium.org/p/chromium/builders/luci.chromium.webrtc.fyi/WebRTC%20Chromium%20FYI%20Android%20Tests%20%28dbg%29%20%28M%20Nexus5X%29/117

Original change's description:
> Remove APM-internal usage of EchoControlMobile
> 
> This is a sibling CL to a similar one for EchoCancellation:
> https://webrtc-review.googlesource.com/c/src/+/97603
> 
>  - EchoControlMobileImpl will no longer inherit EchoControlMobile.
>  - Removes usage of AudioProcessing::echo_control_mobile() inside most of
>    the audio processing module and unit tests.
> 
> The CL breaks audioproc_f backwards compatibility: It can no longer
> use all recorded settings (comfort noise, routing mode), but prints an
> error message when unsupported settings are encountered.
> 
> Tested: audioproc_f with .wav and aecdump inputs.
> Bug: webrtc:9535
> Change-Id: I63c3c81bcaf44021315978e1a0f3e42173b988ce
> Reviewed-on: https://webrtc-review.googlesource.com/101621
> Reviewed-by: Alex Loiko <aleloi@webrtc.org>
> Commit-Queue: Sam Zackrisson <saza@webrtc.org>
> Cr-Commit-Position: refs/heads/master@{#24888}

TBR=saza@webrtc.org,aleloi@webrtc.org

Change-Id: I1f8a27ac291f2cdc16c8daa32e399b74d489dbb9
No-Presubmit: true
No-Tree-Checks: true
No-Try: true
Bug: webrtc:9535
Reviewed-on: https://webrtc-review.googlesource.com/102642
Reviewed-by: Sam Zackrisson <saza@webrtc.org>
Commit-Queue: Sam Zackrisson <saza@webrtc.org>
Cr-Commit-Position: refs/heads/master@{#24895}
diff --git a/modules/audio_processing/audio_processing_impl.cc b/modules/audio_processing/audio_processing_impl.cc
index ac28096..a60cd7e 100644
--- a/modules/audio_processing/audio_processing_impl.cc
+++ b/modules/audio_processing/audio_processing_impl.cc
@@ -679,8 +679,9 @@
 
   public_submodules_->echo_cancellation->Enable(
       config_.echo_canceller.enabled && !config_.echo_canceller.mobile_mode);
-  public_submodules_->echo_control_mobile->Enable(
-      config_.echo_canceller.enabled && config_.echo_canceller.mobile_mode);
+  static_cast<EchoControlMobile*>(public_submodules_->echo_control_mobile.get())
+      ->Enable(config_.echo_canceller.enabled &&
+               config_.echo_canceller.mobile_mode);
 
   public_submodules_->echo_cancellation->set_suppression_level(
       config.echo_canceller.legacy_moderate_suppression_level