Preparation for enabling slimming paint synchronized painting

third_party/WebKit/Source/core/paint/LayerClipRecorderTest.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/LayerClipRecorder.h"
 
 #include "core/layout/LayoutTestHelper.h"
 #include "core/layout/LayoutView.h"
 #include "core/layout/compositing/PaintLayerCompositor.h"
@@ skipping 42 matching lines @@
     ClipRect clipRect((LayoutRect(rect)));
     LayerClipRecorder LayerClipRecorder(context, *layoutView.compositor()->rootLayer()->layoutObject(), DisplayItem::ClipLayerForeground, clipRect, 0, LayoutPoint(), PaintLayerFlags());
     if (!LayoutObjectDrawingRecorder::useCachedDrawingIfPossible(context, layoutView, phase, LayoutPoint())) {
         LayoutObjectDrawingRecorder drawingRecorder(context, layoutView, phase, bound, LayoutPoint());
         context.drawRect(rect);
     }
 }
 
 TEST_F(LayerClipRecorderTest, Single)
 {
+    rootPaintController().invalidateAll();

[Xianzhu, 2015/10/28 18:10:23]

Synchronized painting generates display item for the first layout of about:blank
before the first line of the test is executed. This is to avoid the cache from
affecting the test below.

     GraphicsContext context(rootPaintController());
     LayoutRect bound = layoutView().viewRect();
     EXPECT_EQ((size_t)0, rootPaintController().displayItemList().size());
 
     drawRectInClip(context, layoutView(), PaintPhaseForeground, bound);
     rootPaintController().commitNewDisplayItems();
     EXPECT_EQ((size_t)3, rootPaintController().displayItemList().size());
     EXPECT_TRUE(DisplayItem::isClipType(rootPaintController().displayItemList()[0].type()));
     EXPECT_TRUE(DisplayItem::isDrawingType(rootPaintController().displayItemList()[1].type()));
     EXPECT_TRUE(DisplayItem::isEndClipType(rootPaintController().displayItemList()[2].type()));
 }
 
 TEST_F(LayerClipRecorderTest, Empty)
 {
+    rootPaintController().invalidateAll();
     GraphicsContext context(rootPaintController());
     EXPECT_EQ((size_t)0, rootPaintController().displayItemList().size());
 
     drawEmptyClip(context, layoutView(), PaintPhaseForeground);
     rootPaintController().commitNewDisplayItems();
     EXPECT_EQ((size_t)0, rootPaintController().displayItemList().size());
 }
 
 }
 }