AudioSystem: refactor audio config cache and callbacks

Clean up implementation of audio configuration cache and
callback events from AudioFlinger:

- Define class AudioIoDescriptor for audio input and output
configurations outside of AudioSystem class.
- Do not use void * but an AudioIoDescriptor as argument to
audio config callbacks from AudioFlinger.
- Remove unused configuration events.
- Move AudioSystem audio input and output cache from static singletons to
members of AudioFlingerClient subclass.

Change-Id: I67c196c32c09ce2756af0755ee1fe631040c3270
diff --git a/include/media/AudioIoDescriptor.h b/include/media/AudioIoDescriptor.h
new file mode 100644
index 0000000..2437901
--- /dev/null
+++ b/include/media/AudioIoDescriptor.h
@@ -0,0 +1,52 @@
+/*
+ * Copyright (C) 2015 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#ifndef ANDROID_AUDIO_IO_DESCRIPTOR_H
+#define ANDROID_AUDIO_IO_DESCRIPTOR_H
+
+namespace android {
+
+enum audio_io_config_event {
+    AUDIO_OUTPUT_OPENED,
+    AUDIO_OUTPUT_CLOSED,
+    AUDIO_OUTPUT_CONFIG_CHANGED,
+    AUDIO_INPUT_OPENED,
+    AUDIO_INPUT_CLOSED,
+    AUDIO_INPUT_CONFIG_CHANGED,
+};
+
+// audio input/output descriptor used to cache output configurations in client process to avoid
+// frequent calls through IAudioFlinger
+class AudioIoDescriptor : public RefBase {
+public:
+    AudioIoDescriptor() :
+        mSamplingRate(0), mFormat(AUDIO_FORMAT_DEFAULT), mChannelMask(AUDIO_CHANNEL_NONE),
+        mFrameCount(0), mLatency(0) {}
+
+    virtual ~AudioIoDescriptor() {}
+
+    audio_io_handle_t mIoHandle;
+    uint32_t mSamplingRate;
+    audio_format_t mFormat;
+    audio_channel_mask_t mChannelMask;
+    size_t mFrameCount;
+    uint32_t mLatency;
+};
+
+
+};  // namespace android
+
+#endif  /*ANDROID_AUDIO_IO_DESCRIPTOR_H*/