Unhide exposure compensation API.

bug:2375993
diff --git a/camera/CameraParameters.cpp b/camera/CameraParameters.cpp
index 1bf1759..8439e2b 100644
--- a/camera/CameraParameters.cpp
+++ b/camera/CameraParameters.cpp
@@ -60,7 +60,9 @@
 const char CameraParameters::KEY_HORIZONTAL_VIEW_ANGLE[] = "horizontal-view-angle";
 const char CameraParameters::KEY_VERTICAL_VIEW_ANGLE[] = "vertical-view-angle";
 const char CameraParameters::KEY_EXPOSURE_COMPENSATION[] = "exposure-compensation";
-const char CameraParameters::KEY_SUPPORTED_EXPOSURE_COMPENSATION[] = "exposure-compensation-values";
+const char CameraParameters::KEY_MAX_EXPOSURE_COMPENSATION[] = "max-exposure-compensation";
+const char CameraParameters::KEY_MIN_EXPOSURE_COMPENSATION[] = "min-exposure-compensation";
+const char CameraParameters::KEY_EXPOSURE_COMPENSATION_STEP[] = "exposure-compensation-step";
 
 // Values for white balance settings.
 const char CameraParameters::WHITE_BALANCE_AUTO[] = "auto";