[PE] Detect fragment clip change

Bug: 854783 Cq-Include-Trybots: luci.chromium.try:linux_layout_tests_slimming_paint_v2;master.tryserver.blink:linux_trusty_blink_rel Change-Id: I7ae7d241596f8eedce26ff43b2ee9ff584b911ff Reviewed-on: https://chromium-review.googlesource.com/1123108 Commit-Queue: Xianzhu Wang <wangxianzhu@chromium.org> Reviewed-by: Philip Rogers <pdr@chromium.org> Cr-Commit-Position: refs/heads/master@{#572365}

[PE] Detect fragment clip change
Bug: 854783 Cq-Include-Trybots: luci.chromium.try:linux_layout_tests_slimming_paint_v2;master.tryserver.blink:linux_trusty_blink_rel Change-Id: I7ae7d241596f8eedce26ff43b2ee9ff584b911ff Reviewed-on: https://chromium-review.googlesource.com/1123108 Commit-Queue: Xianzhu Wang <wangxianzhu@chromium.org> Reviewed-by: Philip Rogers <pdr@chromium.org> Cr-Commit-Position: refs/heads/master@{#572365}
0e3be792 · Xianzhu Wang · Commit Bot · 98c28a6f · 0e3be792 · 0e3be792
Commit 0e3be792 authored Jul 03, 2018 by Xianzhu Wang Committed by Commit Bot Jul 03, 2018
4 changed files
--- a/third_party/blink/renderer/core/paint/paint_property_tree_builder.cc
+++ b/third_party/blink/renderer/core/paint/paint_property_tree_builder.cc
@@ -2189,20 +2189,27 @@ void PaintPropertyTreeBuilder::CreateFragmentContextsInFlowThread(
    new_fragment_contexts.push_back(
        ContextForFragment(fragment_clip, logical_top_in_flow_thread));

-    base::Optional<LayoutUnit> old_logical_top_in_flow_thread;
    if (current_fragment_data) {
-      if (const auto* old_fragment = current_fragment_data->NextFragment())
-        old_logical_top_in_flow_thread = old_fragment->LogicalTopInFlowThread();
+      if (!current_fragment_data->NextFragment())
+        fragments_changed = true;
      current_fragment_data = &current_fragment_data->EnsureNextFragment();
    } else {
      current_fragment_data = &object_.GetMutableForPainting().FirstFragment();
-      old_logical_top_in_flow_thread =
-          current_fragment_data->LogicalTopInFlowThread();
    }

-    if (!old_logical_top_in_flow_thread ||
-        *old_logical_top_in_flow_thread != logical_top_in_flow_thread)
-      fragments_changed = true;
+    fragments_changed |= logical_top_in_flow_thread !=
+                         current_fragment_data->LogicalTopInFlowThread();
+    if (!fragments_changed) {
+      const ClipPaintPropertyNode* old_fragment_clip = nullptr;
+      if (const auto* properties = current_fragment_data->PaintProperties())
+        old_fragment_clip = properties->FragmentClip();
+      const base::Optional<LayoutRect>& new_fragment_clip =
+          new_fragment_contexts.back().fragment_clip;
+      fragments_changed =
+          !!old_fragment_clip != !!new_fragment_clip ||
+          (old_fragment_clip && new_fragment_clip &&
+           old_fragment_clip->ClipRect() != ToClipRect(*new_fragment_clip));
+    }

    InitFragmentPaintProperties(
        *current_fragment_data,

--- a/third_party/blink/renderer/core/paint/paint_property_tree_builder_test.cc
+++ b/third_party/blink/renderer/core/paint/paint_property_tree_builder_test.cc
@@ -3591,25 +3591,6 @@ TEST_P(PaintPropertyTreeBuilderTest, MainThreadScrollReasonsWithoutScrolling) {
            nullptr);
 }

-static unsigned NumFragments(const LayoutObject* obj) {
-  unsigned count = 0;
-  auto* fragment = &obj->FirstFragment();
-  while (fragment) {
-    count++;
-    fragment = fragment->NextFragment();
-  }
-  return count;
-}
-
-static const FragmentData& FragmentAt(const LayoutObject* obj, unsigned count) {
-  auto* fragment = &obj->FirstFragment();
-  while (count > 0) {
-    count--;
-    fragment = fragment->NextFragment();
-  }
-  return *fragment;
-}
-
 TEST_P(PaintPropertyTreeBuilderTest, PaintOffsetsUnderMultiColumnScrolled) {
  SetBodyInnerHTML(R"HTML(
    <!doctype HTML>

--- a/third_party/blink/renderer/core/paint/paint_property_tree_builder_test.h
+++ b/third_party/blink/renderer/core/paint/paint_property_tree_builder_test.h
@@ -40,6 +40,26 @@ class PaintPropertyTreeBuilderTest : public PaintControllerPaintTest {

  const ObjectPaintProperties* PaintPropertiesForElement(const char* name);

+  static unsigned NumFragments(const LayoutObject* obj) {
+    unsigned count = 0;
+    auto* fragment = &obj->FirstFragment();
+    while (fragment) {
+      count++;
+      fragment = fragment->NextFragment();
+    }
+    return count;
+  }
+
+  static const FragmentData& FragmentAt(const LayoutObject* obj,
+                                        unsigned count) {
+    auto* fragment = &obj->FirstFragment();
+    while (count > 0) {
+      count--;
+      fragment = fragment->NextFragment();
+    }
+    return *fragment;
+  }
+
 private:
  void SetUp() override;
 };

--- a/third_party/blink/renderer/core/paint/paint_property_tree_update_tests.cc
+++ b/third_party/blink/renderer/core/paint/paint_property_tree_update_tests.cc
@@ -1175,4 +1175,50 @@ TEST_P(PaintPropertyTreeBuilderTest, OmitOverflowClipOnCaretChange) {
  EXPECT_FALSE(PaintPropertiesForElement("target")->OverflowClip());
 }

+TEST_P(PaintPropertyTreeUpdateTest,
+       FragmentClipUpdateOnMulticolContainerWidthChange) {
+  SetBodyInnerHTML(R"HTML(
+    <style>body {margin: 0}</style>
+    <div id="container" style="width: 100px">
+      <div id="multicol" style="columns: 2; column-gap: 0; line-height: 500px">
+        <div><br></div>
+        <div><br></div>
+      </div>
+    </div>
+  )HTML");
+
+  auto* flow_thread = GetLayoutObjectByElementId("multicol")->SlowFirstChild();
+  ASSERT_EQ(2u, NumFragments(flow_thread));
+  EXPECT_EQ(50, FragmentAt(flow_thread, 0)
+                    .PaintProperties()
+                    ->FragmentClip()
+                    ->ClipRect()
+                    .Rect()
+                    .MaxX());
+  EXPECT_EQ(50, FragmentAt(flow_thread, 1)
+                    .PaintProperties()
+                    ->FragmentClip()
+                    ->ClipRect()
+                    .Rect()
+                    .X());
+
+  GetDocument()
+      .getElementById("container")
+      ->setAttribute(HTMLNames::styleAttr, "width: 500px");
+  GetDocument().View()->UpdateAllLifecyclePhases();
+  ASSERT_EQ(2u, NumFragments(flow_thread));
+  EXPECT_EQ(250, FragmentAt(flow_thread, 0)
+                     .PaintProperties()
+                     ->FragmentClip()
+                     ->ClipRect()
+                     .Rect()
+                     .MaxX());
+  EXPECT_EQ(250, FragmentAt(flow_thread, 1)
+                     .PaintProperties()
+                     ->FragmentClip()
+                     ->ClipRect()
+                     .Rect()
+                     .X());
+}
+
 }  // namespace blink