Camera2: Add flush support

- On HAL2 devices, fall back to wait until idle
- On HAL3 devices, call HAL flush method

Bug: 9758581
Change-Id: Ie1c570a15f6590a1ee6c271e3b989c48079b468a
diff --git a/services/camera/libcameraservice/api2/CameraDeviceClient.cpp b/services/camera/libcameraservice/api2/CameraDeviceClient.cpp
index 414316d..289ba06 100644
--- a/services/camera/libcameraservice/api2/CameraDeviceClient.cpp
+++ b/services/camera/libcameraservice/api2/CameraDeviceClient.cpp
@@ -436,6 +436,20 @@
     return res;
 }
 
+status_t CameraDeviceClient::flush() {
+    ATRACE_CALL();
+    ALOGV("%s", __FUNCTION__);
+
+    status_t res = OK;
+    if ( (res = checkPid(__FUNCTION__) ) != OK) return res;
+
+    Mutex::Autolock icl(mBinderSerializationLock);
+
+    if (!mDevice.get()) return DEAD_OBJECT;
+
+    return mDevice->flush();
+}
+
 status_t CameraDeviceClient::dump(int fd, const Vector<String16>& args) {
     String8 result;
     result.appendFormat("CameraDeviceClient[%d] (%p) PID: %d, dump:\n",