Add stable id to PaintImage.

cc/paint/paint_op_buffer_unittest.cc

 // Copyright 2017 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 "cc/paint/paint_op_buffer.h"
 #include "cc/paint/display_item_list.h"
 #include "cc/test/skia_common.h"
 #include "cc/test/test_skcanvas.h"
 #include "testing/gtest/include/gtest/gtest.h"
 
@@ skipping 415 matching lines @@
 
 TEST(PaintOpBufferTest, DiscardableImagesTracking_NoImageOp) {
   PaintOpBuffer buffer;
   PaintFlags flags;
   buffer.push<DrawRectOp>(SkRect::MakeWH(100, 100), flags);
   EXPECT_FALSE(buffer.HasDiscardableImages());
 }
 
 TEST(PaintOpBufferTest, DiscardableImagesTracking_DrawImage) {
   PaintOpBuffer buffer;
-  PaintImage image = PaintImage(CreateDiscardableImage(gfx::Size(100, 100)));
+  PaintImage image = PaintImage(PaintImage::GetNextId(),
+                                CreateDiscardableImage(gfx::Size(100, 100)));
   buffer.push<DrawImageOp>(image, SkIntToScalar(0), SkIntToScalar(0), nullptr);
   EXPECT_TRUE(buffer.HasDiscardableImages());
 }
 
 TEST(PaintOpBufferTest, DiscardableImagesTracking_DrawImageRect) {
   PaintOpBuffer buffer;
-  PaintImage image = PaintImage(CreateDiscardableImage(gfx::Size(100, 100)));
+  PaintImage image = PaintImage(PaintImage::GetNextId(),
+                                CreateDiscardableImage(gfx::Size(100, 100)));
   buffer.push<DrawImageRectOp>(
       image, SkRect::MakeWH(100, 100), SkRect::MakeWH(100, 100), nullptr,
       PaintCanvas::SrcRectConstraint::kFast_SrcRectConstraint);
   EXPECT_TRUE(buffer.HasDiscardableImages());
 }
 
 TEST(PaintOpBufferTest, DiscardableImagesTracking_NestedDrawOp) {
   sk_sp<PaintRecord> record = sk_make_sp<PaintRecord>();
-  PaintImage image = PaintImage(CreateDiscardableImage(gfx::Size(100, 100)));
+  PaintImage image = PaintImage(PaintImage::GetNextId(),
+                                CreateDiscardableImage(gfx::Size(100, 100)));
   record->push<DrawImageOp>(image, SkIntToScalar(0), SkIntToScalar(0), nullptr);
 
   PaintOpBuffer buffer;
   buffer.push<DrawRecordOp>(record);
   EXPECT_TRUE(buffer.HasDiscardableImages());
 
   scoped_refptr<DisplayItemList> list = new DisplayItemList;
   list->CreateAndAppendDrawingItem<DrawingDisplayItem>(
       gfx::Rect(0, 0, 100, 100), record);
   list->Finalize();
   PaintOpBuffer new_buffer;
   new_buffer.push<DrawDisplayItemListOp>(list);
   EXPECT_TRUE(new_buffer.HasDiscardableImages());
 }
 
 TEST(PaintOpBufferTest, DiscardableImagesTracking_OpWithFlags) {
   PaintOpBuffer buffer;
   PaintFlags flags;
   sk_sp<SkImage> image = CreateDiscardableImage(gfx::Size(100, 100));
   flags.setShader(
       image->makeShader(SkShader::kClamp_TileMode, SkShader::kClamp_TileMode));
   buffer.push<DrawRectOp>(SkRect::MakeWH(100, 100), flags);
   EXPECT_TRUE(buffer.HasDiscardableImages());
 }
 
 }  // namespace cc