[SPv2] Reverse PaintArtifactCompositor clip layer origin undo order

third_party/WebKit/Source/platform/graphics/compositing/PaintArtifactCompositor.cpp

 // Copyright 2015 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 "platform/graphics/compositing/PaintArtifactCompositor.h"
 
 #include "cc/layers/content_layer_client.h"
 #include "cc/layers/layer.h"
 #include "cc/layers/layer_settings.h"
 #include "cc/layers/picture_layer.h"
@@ skipping 159 matching lines @@
     gfx::RectF clipRect = node->clipRect().rect();
 
     // TODO(jbroman): This, and the similar logic in
     // PaintArtifactCompositor::update, will need to be updated to account for
     // other kinds of intermediate layers, such as those that apply effects.
     // TODO(jbroman): This assumes that the transform space of this node's
     // parent is an ancestor of this node's transform space. That's not
     // necessarily true, and this should be fixed.
     gfx::Transform transform = transformToTransformSpace(localTransformSpace(node), localTransformSpace(node->parent()));
     gfx::Vector2dF offset = clipRect.OffsetFromOrigin();
+    transform.Translate(offset.x(), offset.y());
     if (node->parent()) {
         FloatPoint offsetDueToParentClipOffset = node->parent()->clipRect().rect().location();
-        offset -= gfx::Vector2dF(offsetDueToParentClipOffset.x(), offsetDueToParentClipOffset.y());
+        gfx::Transform undoClipOffset;
+        undoClipOffset.Translate(-offsetDueToParentClipOffset.x(), -offsetDueToParentClipOffset.y());
+        transform.PreconcatTransform(undoClipOffset);
     }
-    transform.Translate(offset.x(), offset.y());
 
     scoped_refptr<cc::Layer> layer = cc::Layer::Create(cc::LayerSettings());
     layer->SetIsDrawable(false);
     layer->SetMasksToBounds(true);
     layer->SetPosition(gfx::PointF());
     layer->SetBounds(gfx::ToRoundedSize(clipRect.size()));
     layer->SetTransform(transform);
     return layer;
 }
 
@@ skipping 91 matching lines @@
     // The common case: create a layer for painted content.
     gfx::Rect combinedBounds = enclosingIntRect(paintChunk.bounds);
     scoped_refptr<cc::DisplayItemList> displayList = recordPaintChunk(paintArtifact, paintChunk, combinedBounds);
     OwnPtr<ContentLayerClientImpl> contentLayerClient = adoptPtr(
         new ContentLayerClientImpl(std::move(displayList), gfx::Rect(combinedBounds.size())));
 
     // Include the offset in the transform, because it needs to apply in
     // this layer's transform space (whereas layer position applies in its
     // parent's transform space).
     gfx::Vector2dF offset = gfx::PointF(combinedBounds.origin()).OffsetFromOrigin();
+    transform.Translate(offset.x(), offset.y());
+
+    // If a clip was applied, its origin needs to be cancelled out in
+    // this transform.
     if (const auto* clip = paintChunk.properties.clip.get()) {
-        // If a clip was applied, its origin needs to be cancelled out in
-        // this transform.
         FloatPoint offsetDueToClipOffset = clip->clipRect().rect().location();
-        offset -= gfx::Vector2dF(offsetDueToClipOffset.x(), offsetDueToClipOffset.y());
+        gfx::Transform undoClipOffset;
+        undoClipOffset.Translate(-offsetDueToClipOffset.x(), -offsetDueToClipOffset.y());
+        transform.PreconcatTransform(undoClipOffset);
     }
-    transform.Translate(offset.x(), offset.y());
 
     scoped_refptr<cc::PictureLayer> layer = cc::PictureLayer::Create(cc::LayerSettings(), contentLayerClient.get());
     layer->SetBounds(combinedBounds.size());
     layer->SetTransform(transform);
     layer->SetIsDrawable(true);
     layer->SetDoubleSided(!paintChunk.properties.backfaceHidden);
     if (paintChunk.knownToBeOpaque)
         layer->SetContentsOpaque(true);
     m_contentLayerClients.append(contentLayerClient.release());
     return layer;
 }
 
 
 } // namespace blink