V4L2 HALv3 initial check in

Decent outline of an initial HALv3. Still a lot to be filled in.
Adapted from the reference implementation in libhardware.

BUG: 29006356
TEST: Ran simple test program. Connects to the HAL and then
  fails because there are no cameras (expected behavior right now).

Change-Id: I11c7e00dca1bbb6ade6b5a0f55fedac3d2d01695
diff --git a/modules/camera/3_4/V4L2Camera.h b/modules/camera/3_4/V4L2Camera.h
new file mode 100644
index 0000000..4ac9cc4
--- /dev/null
+++ b/modules/camera/3_4/V4L2Camera.h
@@ -0,0 +1,58 @@
+/*
+ * Copyright (C) 2016 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.
+ */
+
+// Loosely based on hardware/libhardware/modules/camera/ExampleCamera.h
+
+#ifndef V4L2_CAMERA_H
+#define V4L2_CAMERA_H
+
+#include <string>
+
+#include <system/camera_metadata.h>
+#include "Camera.h"
+#include "Common.h"
+
+namespace v4l2_camera_hal {
+// V4L2Camera is a specific V4L2-supported camera device. The Camera object
+// contains all logic common between all cameras (e.g. front and back cameras),
+// while a specific camera device (e.g. V4L2Camera) holds all specific
+// metadata and logic about that device.
+class V4L2Camera : public default_camera_hal::Camera {
+public:
+  V4L2Camera(int id, const std::string path);
+  ~V4L2Camera();
+
+private:
+  // default_camera_hal::Camera virtual methods.
+  // Initialize static camera characteristics for individual device.
+  camera_metadata_t *initStaticInfo();
+  // Initialize device info: facing, orientation, resource cost,
+  // and conflicting devices (/conflicting devices length).
+  void initDeviceInfo(camera_info_t* info);
+  // Initialize whole device (templates/etc) when opened.
+  int initDevice();
+  // Verify settings are valid for a capture with this device.
+  bool isValidCaptureSettings(const camera_metadata_t* settings);
+
+  // The camera device path. For example, /dev/video0.
+  const std::string mDevicePath;
+
+  DISALLOW_COPY_AND_ASSIGN(V4L2Camera);
+};
+
+} // namespace v4l2_camera_hal
+
+#endif // V4L2_CAMERA_H