[SPv175+] Fix PaintLayerPaintPainter::AdjustForPaintOffsetTranslation

When the original root layer doesn't have PaintOffsetTranslation,
we need to add the original root layer's paint offset to
paint_dirty_rect.

Bug: 771643
Cq-Include-Trybots: master.tryserver.chromium.linux:linux_layout_tests_slimming_paint_v2
Change-Id: Ife14340612c36edb8206d8f4523f01843b422b6a
Reviewed-on: https://chromium-review.googlesource.com/822031Reviewed-by: Chris Harrelson <chrishtr@chromium.org>
Commit-Queue: Xianzhu Wang <wangxianzhu@chromium.org>
Cr-Commit-Position: refs/heads/master@{#523637}

third_party/WebKit/LayoutTests/TestExpectations

@@ -75,13 +75,10 @@ crbug.com/769942 virtual/spv175/paint/invalidation/svg/image-with-clip-path.svg
 crbug.com/769942 virtual/spv175/paint/invalidation/svg/js-late-clipPath-and-object-creation.svg [ Failure ]
 crbug.com/769942 virtual/spv175/paint/invalidation/svg/js-late-clipPath-creation.svg [ Failure ]
 
-crbug.com/771643 virtual/spv175/compositing/fixed-body-background-positioned.html [ Failure Pass ]
 crbug.com/771643 virtual/spv175/compositing/geometry/repaint-foreground-layer.html [ Crash ]
 crbug.com/771643 virtual/spv175/compositing/images/direct-image-dynamic-border-radius.html [ Failure ]
 crbug.com/771643 virtual/spv175/compositing/overflow/nested-border-radius-clipping.html [ Failure ]
-crbug.com/771643 virtual/spv175/compositing/overflow/scroll-ancestor-update.html [ Failure ]
 crbug.com/771643 virtual/spv175/compositing/overflow/scroll-neg-z-index-and-composited-child.html [ Failure ]
-crbug.com/771643 virtual/spv175/compositing/squashing/squash-composited-input.html [ Failure ]
 crbug.com/771643 virtual/spv175/compositing/squashing/squash-overflow-hidden-scrolltop.html [ Failure ]
 crbug.com/771643 virtual/spv175/compositing/squashing/squash-with-ancestor-reflection.html [ Failure ]
 crbug.com/771643 virtual/spv175/compositing/visibility/visibility-image-layers.html [ Failure Pass ]

third_party/WebKit/Source/core/paint/PaintLayerPainter.cpp

@@ -267,10 +267,20 @@ void PaintLayerPainter::AdjustForPaintOffsetTranslation(
   if (const auto* properties =
           paint_layer_.GetLayoutObject().FirstFragment().PaintProperties()) {
     if (properties->PaintOffsetTranslation()) {
-      painting_info.root_layer = &paint_layer_;
+      // Map paint_dirty_rect from the original root layer to the current layer,
+      // and make the current layer the new root layer.
       painting_info.paint_dirty_rect =
           properties->PaintOffsetTranslation()->Matrix().Inverse().MapRect(
               painting_info.paint_dirty_rect);
+      // If the original root layer doesn't have PaintOffsetTranslation which
+      // means that paint_layer_'s PaintOffsetTranslation includes root layer's
+      // paint offset, then we need to add the root layer's paint offset.
+      const auto& root_fragment =
+          painting_info.root_layer->GetLayoutObject().FirstFragment();
+      if (!root_fragment.PaintProperties() ||
+          !root_fragment.PaintProperties()->PaintOffsetTranslation())
+        painting_info.paint_dirty_rect.MoveBy(root_fragment.PaintOffset());
+      painting_info.root_layer = &paint_layer_;
 
       // TODO(chrishtr): is this correct for fragmentation?
       painting_info.sub_pixel_accumulation = ToLayoutSize(