Camera: Pass system health metrics to ServiceProxy

- Measure session statistics:
  - Camera open, close, and session creation latency
  - Session information such as camera id, is_ndk, operating mode,
    and reconfiguration count.
- Measure stream statistics:
  - width, height, format, dataspace, usage
  - max buffer count
  - buffer loss count
  - startup latency.

Test: ./out/host/linux-x86/bin/statsd_testdrive 227
Test: Camera CTS, VNDK test
Bug: 154159000
Change-Id: I082ef26a312bddbfd4abcc2148728a4b7bf8a9f6
diff --git a/services/camera/libcameraservice/device3/Camera3IOStreamBase.h b/services/camera/libcameraservice/device3/Camera3IOStreamBase.h
index 448379c..ca62239 100644
--- a/services/camera/libcameraservice/device3/Camera3IOStreamBase.h
+++ b/services/camera/libcameraservice/device3/Camera3IOStreamBase.h
@@ -48,6 +48,7 @@
 
     virtual void     dump(int fd, const Vector<String16> &args) const;
 
+    int              getMaxTotalBuffers() const { return mTotalBufferCount; }
   protected:
     size_t            mTotalBufferCount;
     // sum of input and output buffers that are currently acquired by HAL