Remove DstIn optimization when painting mask for inline flow box

Cq-Include-Trybots: master.tryserver.blink:linux_trusty_blink_rel;master.tryserver.chromium.linux:linux_layout_tests_slimming_paint_v2
Change-Id: I7cdba1e84b853eeaff281093555e8757dc1616ed
Reviewed-on: https://chromium-review.googlesource.com/882396Reviewed-by: Tien-Ren Chen <trchen@chromium.org>
Commit-Queue: Xianzhu Wang <wangxianzhu@chromium.org>
Cr-Commit-Position: refs/heads/master@{#532493}

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

@@ -70,8 +70,7 @@ BoxReflection BoxReflectionForPaintLayer(const PaintLayer& layer,
       node = layout_object->GeneratingNode();
     NinePieceImagePainter::Paint(builder.Context(), layer.GetLayoutObject(),
                                  layer.GetLayoutObject().GetDocument(), node,
-                                 mask_rect, style, mask_nine_piece,
-                                 SkBlendMode::kSrcOver);
+                                 mask_rect, style, mask_nine_piece);
   }
   return BoxReflection(direction, offset, builder.EndRecording(),
                        FloatRect(mask_bounding_rect));

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

@@ -363,27 +363,16 @@ void InlineFlowBoxPainter::PaintMask(const PaintInfo& paint_info,
 
   // Figure out if we need to push a transparency layer to render our mask.
   bool push_transparency_layer = false;
-  SkBlendMode composite_op = SkBlendMode::kSrcOver;
+  LayoutRect paint_rect = LayoutRect(adjusted_paint_offset, frame_rect.Size());
   DCHECK(box_model.HasLayer());
   if (!box_model.Layer()->MaskBlendingAppliedByCompositor(paint_info)) {
-    if ((mask_box_image && box_model.StyleRef().MaskLayers().HasImage()) ||
-        box_model.StyleRef().MaskLayers().Next()) {
-      push_transparency_layer = true;
-      paint_info.context.BeginLayer(1.0f, SkBlendMode::kDstIn);
-    } else {
-      // TODO(fmalita): passing a dst-in xfer mode down to
-      // paintFillLayers/paintNinePieceImage seems dangerous: it is only
-      // correct if applied atomically (single draw call). While the heuristic
-      // above presumably ensures that is the case, this approach seems super
-      // fragile. We should investigate dropping this optimization in favour
-      // of the more robust layer branch above.
-      composite_op = SkBlendMode::kDstIn;
-    }
+    push_transparency_layer = true;
+    FloatRect bounds(paint_rect);
+    paint_info.context.BeginLayer(1.0f, SkBlendMode::kDstIn, &bounds);
   }
 
-  LayoutRect paint_rect = LayoutRect(adjusted_paint_offset, frame_rect.Size());
   PaintFillLayers(paint_info, Color::kTransparent,
-                  box_model.StyleRef().MaskLayers(), paint_rect, composite_op);
+                  box_model.StyleRef().MaskLayers(), paint_rect);
 
   bool has_box_image = mask_box_image && mask_box_image->CanRender();
   if (!has_box_image || !mask_box_image->IsLoaded()) {
@@ -398,7 +387,7 @@ void InlineFlowBoxPainter::PaintMask(const PaintInfo& paint_info,
     NinePieceImagePainter::Paint(paint_info.context, box_model,
                                  box_model.GetDocument(), GetNode(&box_model),
                                  paint_rect, box_model.StyleRef(),
-                                 mask_nine_piece_image, composite_op);
+                                 mask_nine_piece_image);
   } else {
     // We have a mask image that spans multiple lines.
     // FIXME: What the heck do we do with RTL here? The math we're using is
@@ -413,7 +402,7 @@ void InlineFlowBoxPainter::PaintMask(const PaintInfo& paint_info,
     NinePieceImagePainter::Paint(paint_info.context, box_model,
                                  box_model.GetDocument(), GetNode(&box_model),
                                  image_strip_paint_rect, box_model.StyleRef(),
-                                 mask_nine_piece_image, composite_op);
+                                 mask_nine_piece_image);
   }
 
   if (push_transparency_layer)

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

@@ -24,8 +24,7 @@ void PaintPieces(GraphicsContext& context,
                  const ComputedStyle& style,
                  const NinePieceImage& nine_piece_image,
                  Image* image,
-                 IntSize image_size,
-                 SkBlendMode op) {
+                 IntSize image_size) {
   IntRectOutsets border_widths(style.BorderTopWidth(), style.BorderRightWidth(),
                                style.BorderBottomWidth(),
                                style.BorderLeftWidth());
@@ -42,12 +41,12 @@ void PaintPieces(GraphicsContext& context,
         // Since there is no way for the developer to specify decode behavior,
         // use kSync by default.
         context.DrawImage(image, Image::kSyncDecode, draw_info.destination,
-                          &draw_info.source, op);
+                          &draw_info.source);
       } else {
         context.DrawTiledImage(image, draw_info.destination, draw_info.source,
                                draw_info.tile_scale,
                                draw_info.tile_rule.horizontal,
-                               draw_info.tile_rule.vertical, op);
+                               draw_info.tile_rule.vertical);
       }
     }
   }
@@ -61,8 +60,7 @@ bool NinePieceImagePainter::Paint(GraphicsContext& graphics_context,
                                   Node* node,
                                   const LayoutRect& rect,
                                   const ComputedStyle& style,
-                                  const NinePieceImage& nine_piece_image,
-                                  SkBlendMode op) {
+                                  const NinePieceImage& nine_piece_image) {
   StyleImage* style_image = nine_piece_image.GetImage();
   if (!style_image)
     return false;
@@ -104,7 +102,7 @@ bool NinePieceImagePainter::Paint(GraphicsContext& graphics_context,
   ScopedInterpolationQuality interpolation_quality_scope(
       graphics_context, style.GetInterpolationQuality());
   PaintPieces(graphics_context, border_image_rect, style, nine_piece_image,
-              image.get(), image_size, op);
+              image.get(), image_size);
 
   return true;
 }

third_party/WebKit/Source/core/paint/NinePieceImagePainter.h

@@ -6,7 +6,6 @@
 #define NinePieceImagePainter_h
 
 #include "platform/heap/Heap.h"
-#include "third_party/skia/include/core/SkBlendMode.h"
 
 namespace blink {
 
@@ -28,8 +27,7 @@ class NinePieceImagePainter {
                     Node*,
                     const LayoutRect&,
                     const ComputedStyle&,
-                    const NinePieceImage&,
-                    SkBlendMode = SkBlendMode::kSrcOver);
+                    const NinePieceImage&);
 
  private:
   NinePieceImagePainter() = default;