Merge "[GraphicsEnvironment] Avoid null access." into rvc-qpr-dev am: 23ace73ac4

Original change: https://googleplex-android-review.googlesource.com/c/platform/frameworks/base/+/13229183

MUST ONLY BE SUBMITTED BY AUTOMERGER

Change-Id: I20f201739a456f9580328670189e506e284feb2e

core/java/android/os/GraphicsEnvironment.java

@@ -249,6 +249,7 @@ public class GraphicsEnvironment {
         }
         if (appInfo == null) {
             Log.w(TAG, "Debug layer app '" + packageName + "' not installed");
+            return "";
         }
 
         final String abi = chooseAbi(appInfo);