Bump to WebRTC M131 release

Ongoing fixes and improvements, transient suppressor is gone. Also,
dropping isac because it doesn't seem to be useful, and is just build
system deadweight now.

Upstream references:

  Version: 131.0.6778.200
  WebRTC: 79aff54b0fa9238ce3518dd9eaf9610cd6f22e82
  Chromium: 2a19506ad24af755f2a215a4c61f775393e0db42

webrtc/common_audio/channel_buffer.h

@@ -23,6 +23,44 @@
 
 namespace webrtc {
 
+// TODO: b/335805780 - Remove this method. Instead, use Deinterleave() from
+// audio_util.h which requires size checked buffer views.
+template <typename T>
+void Deinterleave(const T* interleaved,
+                  size_t samples_per_channel,
+                  size_t num_channels,
+                  T* const* deinterleaved) {
+  for (size_t i = 0; i < num_channels; ++i) {
+    T* channel = deinterleaved[i];
+    size_t interleaved_idx = i;
+    for (size_t j = 0; j < samples_per_channel; ++j) {
+      channel[j] = interleaved[interleaved_idx];
+      interleaved_idx += num_channels;
+    }
+  }
+}
+
+// `Interleave()` variant for cases where the deinterleaved channels aren't
+// represented by a `DeinterleavedView`.
+// TODO: b/335805780 - Remove this method. Instead, use Deinterleave() from
+// audio_util.h which requires size checked buffer views.
+template <typename T>
+void Interleave(const T* const* deinterleaved,
+                size_t samples_per_channel,
+                size_t num_channels,
+                InterleavedView<T>& interleaved) {
+  RTC_DCHECK_EQ(NumChannels(interleaved), num_channels);
+  RTC_DCHECK_EQ(SamplesPerChannel(interleaved), samples_per_channel);
+  for (size_t i = 0; i < num_channels; ++i) {
+    const T* channel = deinterleaved[i];
+    size_t interleaved_idx = i;
+    for (size_t j = 0; j < samples_per_channel; ++j) {
+      interleaved[interleaved_idx] = channel[j];
+      interleaved_idx += num_channels;
+    }
+  }
+}
+
 // Helper to encapsulate a contiguous data buffer, full or split into frequency
 // bands, with access to a pointer arrays of the deinterleaved channels and
 // bands. The buffer is zero initialized at creation.