aaudio: use new flowgraph to simplify processing

Construct a flowgraph based on the source and destination
format and channelCount. This is groundwork for supporting 24-bit
PCM formats.

Also cleaned up handling of device related format.

This CL removes more code than it adds.

Bug: 65067568
Test: write_sine_callback.cpp -pl
Test: write_sine_callback.cpp -pl -x
Test: input_monitor -pl
Test: input_monitor -pl -x
Change-Id: Ia155bff0164912011d09b61b54f983ccf4490bd1
diff --git a/media/libaaudio/src/client/AudioStreamInternal.h b/media/libaaudio/src/client/AudioStreamInternal.h
index 0425cd5..3bb9e1e 100644
--- a/media/libaaudio/src/client/AudioStreamInternal.h
+++ b/media/libaaudio/src/client/AudioStreamInternal.h
@@ -27,7 +27,6 @@
 #include "client/AudioEndpoint.h"
 #include "core/AudioStream.h"
 #include "utility/AudioClock.h"
-#include "utility/LinearRamp.h"
 
 using android::sp;
 using android::IAAudioService;
@@ -193,6 +192,8 @@
 
     int64_t                  mServiceLatencyNanos = 0;
 
+    // Sometimes the hardware is operating with a different channel count from the app.
+    // Then we require conversion in AAudio.
     int32_t                  mDeviceChannelCount = 0;
 };