Handle bitmap==null in PdfRenderer.Page#render.

Change-Id: Ie24ca45d4b5e27d5e99de72115e8e00b32b30655
diff --git a/graphics/java/android/graphics/pdf/PdfRenderer.java b/graphics/java/android/graphics/pdf/PdfRenderer.java
index 7f115b5..6b7e1b2 100644
--- a/graphics/java/android/graphics/pdf/PdfRenderer.java
+++ b/graphics/java/android/graphics/pdf/PdfRenderer.java
@@ -27,6 +27,7 @@
 import android.os.ParcelFileDescriptor;
 import android.system.ErrnoException;
 import android.system.OsConstants;
+import com.android.internal.util.Preconditions;
 import dalvik.system.CloseGuard;
 import libcore.io.Libcore;
 
@@ -375,6 +376,8 @@
                            @Nullable Matrix transform, @RenderMode int renderMode) {
             throwIfClosed();
 
+            destination = Preconditions.checkNotNull(destination, "bitmap null");
+
             if (destination.getConfig() != Config.ARGB_8888) {
                 throw new IllegalArgumentException("Unsupported pixel format");
             }