Add focal length and view angle API.

bug:2375989,2375987
diff --git a/libs/ui/CameraParameters.cpp b/libs/ui/CameraParameters.cpp
index a94f6b9..495e164 100644
--- a/libs/ui/CameraParameters.cpp
+++ b/libs/ui/CameraParameters.cpp
@@ -56,6 +56,9 @@
 const char CameraParameters::KEY_SUPPORTED_FLASH_MODES[] = "flash-mode-values";
 const char CameraParameters::KEY_FOCUS_MODE[] = "focus-mode";
 const char CameraParameters::KEY_SUPPORTED_FOCUS_MODES[] = "focus-mode-values";
+const char CameraParameters::KEY_FOCAL_LENGTH[] = "focal-length";
+const char CameraParameters::KEY_HORIZONTAL_VIEW_ANGLE[] = "horizontal-view-angle";
+const char CameraParameters::KEY_VERTICAL_VIEW_ANGLE[] = "vertical-view-angle";
 
 // Values for white balance settings.
 const char CameraParameters::WHITE_BALANCE_AUTO[] = "auto";