Add video snapshot camera parameter.

The API is still hidden.

bug:5187868

Change-Id: I59e1b5774ca32be049723d1a0887faa90d8884bb
diff --git a/libs/camera/CameraParameters.cpp b/libs/camera/CameraParameters.cpp
index 0eb5d50..0dcab6b 100644
--- a/libs/camera/CameraParameters.cpp
+++ b/libs/camera/CameraParameters.cpp
@@ -87,6 +87,7 @@
 const char CameraParameters::KEY_MAX_NUM_DETECTED_FACES_HW[] = "max-num-detected-faces-hw";
 const char CameraParameters::KEY_MAX_NUM_DETECTED_FACES_SW[] = "max-num-detected-faces-sw";
 const char CameraParameters::KEY_RECORDING_HINT[] = "recording-hint";
+const char CameraParameters::KEY_VIDEO_SNAPSHOT_SUPPORTED[] = "video-snapshot-supported";
 
 const char CameraParameters::TRUE[] = "true";
 const char CameraParameters::FALSE[] = "false";