Emit dummy display item when recorded picture is empty

Source/core/paint/DrawingRecorderTest.cpp

 // Copyright 2014 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "config.h"
 #include "core/paint/RenderDrawingRecorder.h"
 
 #include "core/rendering/RenderLayer.h"
 #include "core/rendering/RenderView.h"
 #include "core/rendering/RenderingTestHelper.h"
@@ skipping 43 matching lines @@
 }
 
 
 TEST_F(DrawingRecorderTest, DrawingRecorderTest_Nothing)
 {
     GraphicsContext context(nullptr, &rootDisplayItemList());
     FloatRect bound = renderView()->viewRect();
     EXPECT_EQ((size_t)0, rootDisplayItemList().paintList().size());
 
     drawNothing(&context, renderView(), PaintPhaseForeground, bound);
-    EXPECT_EQ((size_t)0, rootDisplayItemList().paintList().size());
+    EXPECT_EQ((size_t)1, rootDisplayItemList().paintList().size());
+#ifndef NDEBUG
+    EXPECT_STREQ("Dummy", rootDisplayItemList().paintList()[0]->name());
+#endif
 }
 
 TEST_F(DrawingRecorderTest, DrawingRecorderTest_Rect)
 {
     GraphicsContext context(nullptr, &rootDisplayItemList());
     FloatRect bound = renderView()->viewRect();
     drawRect(&context, renderView(), PaintPhaseForeground, bound);
     EXPECT_EQ((size_t)1, rootDisplayItemList().paintList().size());
+#ifndef NDEBUG
+    EXPECT_STREQ("Drawing", rootDisplayItemList().paintList()[0]->name());
+#endif
+}
+
+TEST_F(DrawingRecorderTest, DrawingRecorderTest_Cached)
+{
+    GraphicsContext context(nullptr, &rootDisplayItemList());
+    FloatRect bound = renderView()->viewRect();
+    drawNothing(&context, renderView(), PaintPhaseBlockBackground, bound);
+    drawRect(&context, renderView(), PaintPhaseForeground, bound);
+    EXPECT_EQ((size_t)2, rootDisplayItemList().paintList().size());
+#ifndef NDEBUG
+    EXPECT_STREQ("Dummy", rootDisplayItemList().paintList()[0]->name());
+    EXPECT_STREQ("Drawing", rootDisplayItemList().paintList()[1]->name());
+#endif
+
+    drawNothing(&context, renderView(), PaintPhaseBlockBackground, bound);
+    drawRect(&context, renderView(), PaintPhaseForeground, bound);
+    EXPECT_EQ((size_t)2, rootDisplayItemList().paintList().size());
+#ifndef NDEBUG
+    EXPECT_STREQ("Dummy", rootDisplayItemList().paintList()[0]->name());
+    EXPECT_STREQ("Drawing", rootDisplayItemList().paintList()[1]->name());
+#endif
 }
 
 }
 }