SkRecordDraw: don't bother clipping an empty clip down further

tests/RecordDrawTest.cpp

 #include "Test.h"
 
 #include "SkDebugCanvas.h"
 #include "SkRecord.h"
 #include "SkRecordCulling.h"
 #include "SkRecordDraw.h"
 #include "SkRecorder.h"
 #include "SkRecords.h"
 
 static const int W = 1920, H = 1080;
@@ skipping 25 matching lines @@
 
     // We'll keep the clipRect call from above, and the outer two drawRects, and the push/pop pair.
     // If culling weren't working, we'd see 8 commands recorded here.
     REPORTER_ASSERT(r, 5 == rerecord.count());
 }
 
 DEF_TEST(RecordDraw_Clipping, r) {
     SkRecord record;
     SkRecorder recorder(SkRecorder::kWriteOnly_Mode, &record, W, H);
 
-    // 8 draw commands.
-    // The inner clipRect makes the clip empty, so the inner drawRect does nothing.
+    // 9 draw commands.
     recorder.save();
         recorder.clipRect(SkRect::MakeLTRB(0, 0, 100, 100));
         recorder.drawRect(SkRect::MakeLTRB(20, 20, 40, 40), SkPaint());
         recorder.save();
+            // This first clipRect makes the clip empty, so the next two commands do nothing.
             recorder.clipRect(SkRect::MakeLTRB(200, 200, 300, 300));
-            recorder.drawRect(SkRect::MakeLTRB(220, 220, 240, 240), SkPaint());
+            recorder.clipRect(SkRect::MakeLTRB(210, 210, 250, 250));              // Skipped
+            recorder.drawRect(SkRect::MakeLTRB(220, 220, 240, 240), SkPaint());   // Skipped
         recorder.restore();
     recorder.restore();
 
     // Same deal as above: we need full SkCanvas semantics for clip skipping to work.
     SkRecord rerecord;
     SkRecorder rerecorder(SkRecorder::kReadWrite_Mode, &rerecord, W, H);
     SkRecordDraw(record, &rerecorder);
 
-    // All commands except the drawRect will be preserved.
+    // All commands except the two marked // Skipped above will be preserved.
     REPORTER_ASSERT(r, 7 == rerecord.count());
 }