Define new AudioControl HAL for automotive.

This provides a mechanism for Android to interact with a car's
audio subsystem.
It is a partial replacement for the deprecated AUDIO_* properties in VehicleHal.
It also provides control over fade/balance.

Bug: 31623564
Test: build for bat_land.  VTS tests in future CL.
Change-Id: I4344cce3a6aa9a28d1327bf4d16bd080c7fd3f50
diff --git a/automotive/audiocontrol/1.0/default/AudioControl.h b/automotive/audiocontrol/1.0/default/AudioControl.h
new file mode 100644
index 0000000..3383875
--- /dev/null
+++ b/automotive/audiocontrol/1.0/default/AudioControl.h
@@ -0,0 +1,45 @@
+#ifndef ANDROID_HARDWARE_AUTOMOTIVE_AUDIOCONTROL_V1_0_AUDIOCONTROL_H
+#define ANDROID_HARDWARE_AUTOMOTIVE_AUDIOCONTROL_V1_0_AUDIOCONTROL_H
+
+#include <android/hardware/automotive/audiocontrol/1.0/IAudioControl.h>
+#include <hidl/MQDescriptor.h>
+#include <hidl/Status.h>
+
+namespace android {
+namespace hardware {
+namespace automotive {
+namespace audiocontrol {
+namespace V1_0 {
+namespace implementation {
+
+using ::android::hardware::hidl_array;
+using ::android::hardware::hidl_memory;
+using ::android::hardware::hidl_string;
+using ::android::hardware::hidl_vec;
+using ::android::hardware::Return;
+using ::android::hardware::Void;
+using ::android::sp;
+
+struct AudioControl : public IAudioControl {
+public:
+    // Methods from ::android::hardware::automotive::audiocontrol::V1_0::IAudioControl follow.
+    Return<AudioResult> setCallback(const sp<IAudioControlCallback>& notificationObject) override;
+    Return<int32_t> getBusForContext(uint32_t contextNumber) override;
+    Return<void> setBalanceTowardRight(float value) override;
+    Return<void> setFadeTowardFront(float value) override;
+
+    // Implementation details
+    AudioControl();
+
+private:
+    sp<IAudioControlCallback> callback;
+};
+
+}  // namespace implementation
+}  // namespace V1_0
+}  // namespace audiocontrol
+}  // namespace automotive
+}  // namespace hardware
+}  // namespace android
+
+#endif  // ANDROID_HARDWARE_AUTOMOTIVE_AUDIOCONTROL_V1_0_AUDIOCONTROL_H