Reland: Don't early out recursion into PaintLayerChildren when computing composited bounds.

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

Index: third_party/WebKit/Source/core/paint/PaintLayerClipperTest.cpp
diff --git a/third_party/WebKit/Source/core/paint/PaintLayerClipperTest.cpp b/third_party/WebKit/Source/core/paint/PaintLayerClipperTest.cpp
index f8f5b6e3176bff24244369cacd9bb208c743d212..65a57b663409e43ad82bb08d7b8a27a5f508e229 100644
--- a/third_party/WebKit/Source/core/paint/PaintLayerClipperTest.cpp
+++ b/third_party/WebKit/Source/core/paint/PaintLayerClipperTest.cpp
@@ -116,4 +116,28 @@ TEST_F(PaintLayerClipperTest, NestedContainPaintClip) {
   EXPECT_EQ(LayoutRect(0, 0, 200, 400), layerBounds);
 }
 
+TEST_F(PaintLayerClipperTest, LocalClipRectFixedUnderTransform) {
+  setBodyInnerHTML(
+      "<div id='transformed'"
+      "    style='will-change: transform; width: 100px; height: 100px;"
+      "    overflow: hidden'>"
+      "  <div id='fixed' "
+      "      style='position: fixed; width: 100px; height: 100px;"
+      "      top: -50px'>"
+      "   </div>"
+      "</div>");
+
+  LayoutRect infiniteRect(LayoutRect::infiniteIntRect());
+  PaintLayer* transformed =
+      toLayoutBoxModelObject(getLayoutObjectByElementId("transformed"))
+          ->layer();
+  PaintLayer* fixed =
+      toLayoutBoxModelObject(getLayoutObjectByElementId("fixed"))->layer();
+
+  EXPECT_EQ(LayoutRect(0, 0, 100, 100),
+            transformed->clipper().localClipRect(transformed));
+  EXPECT_EQ(LayoutRect(0, 50, 100, 100),
+            fixed->clipper().localClipRect(transformed));
+}
+
 }  // namespace blink