[PE] Remove extra iframe invalidation on slow scrolls

LocalFrameView::ScrollContentsSlowPath had an invalidation for
iframes but this invalidation was already handled will full
invalidation. This patch removes this extra invalidation.

This makes the root layer scrolling (RLS) and non-RLS
expectations match because this extra invalidation was not
issued for RLS.

Bug: 781419
Change-Id: I2e6bf51682e24b2e2dfa8b56abffa7665ab2bcf4
Cq-Include-Trybots: master.tryserver.chromium.linux:linux_layout_tests_root_layer_scrolls
Reviewed-on: https://chromium-review.googlesource.com/795183Reviewed-by: Xianzhu Wang <wangxianzhu@chromium.org>
Commit-Queue: Philip Rogers <pdr@chromium.org>
Cr-Commit-Position: refs/heads/master@{#520191}

third_party/WebKit/LayoutTests/FlagExpectations/root-layer-scrolls

@@ -52,7 +52,6 @@ crbug.com/417782 inspector-protocol/dom-snapshot/dom-snapshot-getSnapshot.js [ F
 crbug.com/417782 inspector-protocol/layers/paint-profiler.js [ Crash ]
 crbug.com/417782 inspector-protocol/page/get-layout-metrics.js [ Failure ]
 crbug.com/417782 paint/invalidation/resize-iframe-text.html [ Failure ]
-crbug.com/417782 paint/invalidation/scroll/iframe-scroll-repaint.html [ Failure ]
 crbug.com/417782 paint/invalidation/scroll/overflow-scroll-body-appear.html [ Failure ]
 crbug.com/417782 paint/invalidation/svg/absolute-sized-document-no-scrollbars.svg [ Failure ]
 crbug.com/417782 paint/invalidation/svg/deep-nested-embedded-svg-size-changes-no-layout-triggers-1.html [ Failure ]

third_party/WebKit/LayoutTests/paint/invalidation/scroll/iframe-scroll-repaint-expected.txt

 {
   "objectPaintInvalidations": [
-    {
-      "object": "LayoutIFrame IFRAME",
-      "reason": "invalidate paint rectangle"
-    },
     {
       "object": "LayoutView #document",
       "reason": "subtree"

third_party/WebKit/LayoutTests/platform/linux/paint/invalidation/scroll/repaint-during-scroll-with-zoom-expected.txt

@@ -6,11 +6,6 @@
       "contentsOpaque": true,
       "backgroundColor": "#C0C0C0",
       "paintInvalidations": [
-        {
-          "object": "LayoutIFrame (positioned) IFRAME",
-          "rect": [2, 65, 236, 235],
-          "reason": "invalidate paint rectangle"
-        },
         {
           "object": "LayoutBlockFlow BODY",
           "rect": [3, 65, 235, 235],
@@ -45,10 +40,6 @@
     }
   ],
   "objectPaintInvalidations": [
-    {
-      "object": "LayoutIFrame (positioned) IFRAME",
-      "reason": "invalidate paint rectangle"
-    },
     {
       "object": "HorizontalScrollbar",
       "reason": "scroll control"

third_party/WebKit/LayoutTests/platform/mac/paint/invalidation/scroll/repaint-during-scroll-with-zoom-expected.txt

@@ -6,11 +6,6 @@
       "contentsOpaque": true,
       "backgroundColor": "#C0C0C0",
       "paintInvalidations": [
-        {
-          "object": "LayoutIFrame (positioned) IFRAME",
-          "rect": [2, 65, 236, 235],
-          "reason": "invalidate paint rectangle"
-        },
         {
           "object": "LayoutBlockFlow BODY",
           "rect": [3, 65, 235, 235],
@@ -45,10 +40,6 @@
     }
   ],
   "objectPaintInvalidations": [
-    {
-      "object": "LayoutIFrame (positioned) IFRAME",
-      "reason": "invalidate paint rectangle"
-    },
     {
       "object": "HorizontalScrollbar",
       "reason": "scroll control"

third_party/WebKit/LayoutTests/platform/win/paint/invalidation/scroll/repaint-during-scroll-with-zoom-expected.txt

@@ -6,11 +6,6 @@
       "contentsOpaque": true,
       "backgroundColor": "#C0C0C0",
       "paintInvalidations": [
-        {
-          "object": "LayoutIFrame (positioned) IFRAME",
-          "rect": [2, 65, 236, 235],
-          "reason": "invalidate paint rectangle"
-        },
         {
           "object": "LayoutBlockFlow BODY",
           "rect": [3, 65, 235, 235],
@@ -45,10 +40,6 @@
     }
   ],
   "objectPaintInvalidations": [
-    {
-      "object": "LayoutIFrame (positioned) IFRAME",
-      "reason": "invalidate paint rectangle"
-    },
     {
       "object": "HorizontalScrollbar",
       "reason": "scroll control"

third_party/WebKit/Source/core/frame/LocalFrameView.cpp

@@ -1876,17 +1876,6 @@ void LocalFrameView::ScrollContentsSlowPath() {
     DCHECK(!GetLayoutViewItem().IsNull());
     GetLayoutViewItem().InvalidatePaintRectangle(LayoutRect(update_rect));
   }
-  LayoutEmbeddedContentItem frame_layout_item = frame_->OwnerLayoutItem();
-  if (!frame_layout_item.IsNull()) {
-    if (IsEnclosedInCompositingLayer()) {
-      LayoutRect rect(
-          frame_layout_item.BorderLeft() + frame_layout_item.PaddingLeft(),
-          frame_layout_item.BorderTop() + frame_layout_item.PaddingTop(),
-          LayoutUnit(VisibleWidth()), LayoutUnit(VisibleHeight()));
-      frame_layout_item.InvalidatePaintRectangle(rect);
-      return;
-    }
-  }
 }
 
 void LocalFrameView::RestoreScrollbar() {