Camera: Guard against asBinder() calls on NULL interfaces

Bug: 18207548
Change-Id: I9879c9b4c0282a6b96b77398f62beedc47f7f0a0
diff --git a/services/camera/libcameraservice/api1/Camera2Client.cpp b/services/camera/libcameraservice/api1/Camera2Client.cpp
index 2a6aa7b..dd2f64d 100644
--- a/services/camera/libcameraservice/api1/Camera2Client.cpp
+++ b/services/camera/libcameraservice/api1/Camera2Client.cpp
@@ -165,7 +165,8 @@
     String8 result;
     result.appendFormat("Client2[%d] (%p) Client: %s PID: %d, dump:\n",
             mCameraId,
-            getRemoteCallback()->asBinder().get(),
+            (getRemoteCallback() != NULL ?
+                    getRemoteCallback()->asBinder().get() : NULL),
             String8(mClientPackageName).string(),
             mClientPid);
     result.append("  State: ");