Use public APIs for decoding images for screencap

HWUI is restricting access to only a set of stable C APIs. Callers like
boot animation are being converted to either the stable C or NDK APIs.

Test: build and verify screencap cmd line for launcher
Bug: 150782769
Change-Id: I87e1752409ccfeef22a082c389902b0883ad2bee
diff --git a/cmds/screencap/Android.bp b/cmds/screencap/Android.bp
index 248c675..fc628a6 100644
--- a/cmds/screencap/Android.bp
+++ b/cmds/screencap/Android.bp
@@ -7,7 +7,7 @@
         "libcutils",
         "libutils",
         "libbinder",
-        "libhwui",
+        "libjnigraphics",
         "libui",
         "libgui",
     ],