PrintSpooler: fix monkey crash if height&width small than 0

During the monkey test, should add check height & width before
create the bitmap, to avoid the monkey test fail.

Change-Id: I5619c30af63afa3d74d0417e37c67c4920e099ba
Test: build & run

packages/PrintSpooler/src/com/android/printspooler/ui/PageAdapter.java

@@ -467,6 +467,12 @@ public final class PageAdapter extends Adapter<ViewHolder> {
         loadingContent.layout(0, 0, loadingContent.getMeasuredWidth(),
                 loadingContent.getMeasuredHeight());
 
+        // To create a bitmap, height & width should be larger than 0
+        if (mPageContentHeight <= 0 || mPageContentWidth <= 0) {
+            Log.w(LOG_TAG, "Unable to create bitmap, height or width smaller than 0!");
+            return;
+        }
+
         Bitmap loadingBitmap = Bitmap.createBitmap(mPageContentWidth, mPageContentHeight,
                 Bitmap.Config.ARGB_8888);
         loadingContent.draw(new Canvas(loadingBitmap));