Don't allow incremental LayoutView invalidation w/transform.

Bug: 1045421

Change-Id: Ic152bb2d1c88e34e3de012b4da9164ca1ff822ee
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2079304
Auto-Submit: Chris Harrelson <chrishtr@chromium.org>
Commit-Queue: Xianzhu Wang <wangxianzhu@chromium.org>
Reviewed-by: Xianzhu Wang <wangxianzhu@chromium.org>
Cr-Commit-Position: refs/heads/master@{#745483}

third_party/blink/renderer/core/paint/box_paint_invalidator.cc

@@ -250,18 +250,31 @@ BoxPaintInvalidator::ComputeViewBackgroundInvalidation() {
       layout_view.BackgroundNeedsFullPaintInvalidation())
     return BackgroundInvalidationType::kFull;
 
-  // LayoutView's non-fixed-attachment background is positioned in the
-  // document element and needs to invalidate if the size changes.
-  // See: https://drafts.csswg.org/css-backgrounds-3/#root-background.
-  if (BackgroundGeometryDependsOnLayoutOverflowRect()) {
-    Element* document_element = box_.GetDocument().documentElement();
+  if (Element* document_element = box_.GetDocument().documentElement()) {
     if (document_element) {
-      const auto* document_background = document_element->GetLayoutObject();
-      if (document_background && document_background->IsBox()) {
-        const auto* document_background_box = ToLayoutBox(document_background);
-        if (ShouldFullyInvalidateBackgroundOnLayoutOverflowChange(
-                document_background_box->PreviousPhysicalLayoutOverflowRect(),
-                document_background_box->PhysicalLayoutOverflowRect())) {
+      if (const auto* document_element_object =
+              document_element->GetLayoutObject()) {
+        // LayoutView's non-fixed-attachment background is positioned in the
+        // document element and needs to invalidate if the size changes.
+        // See: https://drafts.csswg.org/css-backgrounds-3/#root-background.
+        if (BackgroundGeometryDependsOnLayoutOverflowRect()) {
+          if (document_element_object->IsBox()) {
+            const auto* document_background_box =
+                ToLayoutBox(document_element_object);
+            if (ShouldFullyInvalidateBackgroundOnLayoutOverflowChange(
+                    document_background_box
+                        ->PreviousPhysicalLayoutOverflowRect(),
+                    document_background_box->PhysicalLayoutOverflowRect())) {
+              return BackgroundInvalidationType::kFull;
+            }
+          }
+        }
+
+        // The document background paints with a transform but nevertheless
+        // extended onto an infinite canvas. In cases where it has a transform
+        // we cna't apply incremental invalidation, because the visual rect is
+        // no longer axis-aligned to the LayoutView.
+        if (document_element_object->StyleRef().HasTransform()) {
           return BackgroundInvalidationType::kFull;
         }
       }

third_party/blink/renderer/core/paint/paint_and_raster_invalidation_test.cc

@@ -440,6 +440,31 @@ TEST_P(PaintAndRasterInvalidationTest, NonCompositedLayoutViewResize) {
   GetDocument().View()->SetTracksRasterInvalidations(false);
 }
 
+TEST_P(PaintAndRasterInvalidationTest, FullInvalidationWithHTMLTransform) {
+  GetDocument().documentElement()->setAttribute(html_names::kStyleAttr,
+                                                "transform: scale(0.5)");
+  const DisplayItemClient* client =
+      &GetDocument()
+           .View()
+           ->GetLayoutView()
+           ->GetScrollableArea()
+           ->GetScrollingBackgroundDisplayItemClient();
+  UpdateAllLifecyclePhasesForTest();
+
+  GetDocument().View()->SetTracksRasterInvalidations(true);
+  GetDocument().View()->Resize(WebSize(500, 500));
+  UpdateAllLifecyclePhasesForTest();
+
+  EXPECT_THAT(GetRasterInvalidationTracking()->Invalidations(),
+              UnorderedElementsAre(
+                  RasterInvalidationInfo{client, client->DebugName(),
+                                         IntRect(0, 0, 500, 500),
+                                         PaintInvalidationReason::kBackground},
+                  RasterInvalidationInfo{
+                      client, client->DebugName(), IntRect(0, 0, 500, 500),
+                      PaintInvalidationReason::kPaintProperty}));
+}
+
 TEST_P(PaintAndRasterInvalidationTest, NonCompositedLayoutViewGradientResize) {
   SetBodyInnerHTML(R"HTML(
     <style>