SkRecordDraw: skip draw ops when the clip is empty

dm/DMRecordTask.cpp

Index: dm/DMRecordTask.cpp
diff --git a/dm/DMRecordTask.cpp b/dm/DMRecordTask.cpp
index d38fc4ca23f003ab1cb7cfa3d707c08592d6872f..fb0e4e6898570fab2710773535f15f66290db998 100644
--- a/dm/DMRecordTask.cpp
+++ b/dm/DMRecordTask.cpp
@@ -19,7 +19,8 @@ RecordTask::RecordTask(const Task& parent, skiagm::GM* gm, SkBitmap reference)
 void RecordTask::draw() {
     // Record the GM into an SkRecord.
     SkRecord record;
-    SkRecorder canvas(&record, fReference.width(), fReference.height());
+    SkRecorder canvas(SkRecorder::kWriteOnly_Mode, &record,
+                      fReference.width(), fReference.height());
     canvas.concat(fGM->getInitialTransform());
     fGM->draw(&canvas);