Android Camera API2 Open Flow
流程说明：
Camera App调用CameraManager的openCamera方法，调用到CameraService的connectDevice，然后创建CameraDeviceClient，在Camera2ClientBase的initializeImpl中创建AidlCamera3Device，然后在AidlCamera3Device的initialize方法中调用CameraProviderManager的openAidlSession方法，进而通过ICameraDevice的open方法调用到HAL去执行Open Camera动作。
AidlCamera3Device::initialize() Flow
| Main Task | Description |
|---|---|
| 创建Session | 与HAL交互打开Camera |
| CAMERA CHARACTERISTICS | 获取静态Metadata，判断是否支持 •mSupportNativeZoomRatio •mIsCompositeJpegRDisabled |
| LOGICAL MULTI-CAMERA CONFIGURATION | 如果是Logical Multicam，则对mPhysicalDeviceInfoMap，mDistortionMappers 和 mZoomRatioMappers，mUHRCropAndMeteringRegionMappers进行相应的赋值 |
| METADATA QUEUES | 初始化Metadata Queue，通过FMQ (Fast Message Queue) 用共享内存的方式来传递CaptureRequest和CaptureResult Metadata Buffer |
Camera3Device::initializeCommonLocked() Flow
| Main Task | Description |
|---|---|
| 线程管理 | •StatusTracker •Request Thread •Preparer Thread •CameraServiceWatchdog |