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/BUILD.gn b/modules/audio_processing/BUILD.gn
index 84b8906..78e0091 100644
--- a/modules/audio_processing/BUILD.gn
+++ b/modules/audio_processing/BUILD.gn
@@ -345,7 +345,6 @@
       "audio_frame_view_unittest.cc",
       "config_unittest.cc",
       "echo_cancellation_impl_unittest.cc",
-      "echo_control_mobile_unittest.cc",
       "gain_controller2_unittest.cc",
       "splitting_filter_unittest.cc",
       "test/fake_recording_device_unittest.cc",
@@ -432,7 +431,7 @@
         "audio_processing_impl_unittest.cc",
         "audio_processing_unittest.cc",
         "echo_cancellation_bit_exact_unittest.cc",
-        "echo_control_mobile_bit_exact_unittest.cc",
+        "echo_control_mobile_unittest.cc",
         "echo_detector/circular_buffer_unittest.cc",
         "echo_detector/mean_variance_estimator_unittest.cc",
         "echo_detector/moving_max_unittest.cc",