Shifting layer position for sticky element to avoid passing unnessary variable to cc

third_party/WebKit/Source/core/layout/compositing/CompositedLayerMappingTest.cpp

 // Copyright 2014 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 "core/layout/compositing/CompositedLayerMapping.h"
 
 #include "core/frame/LocalFrameView.h"
 #include "core/layout/LayoutBoxModelObject.h"
 #include "core/layout/LayoutTestHelper.h"
 #include "core/layout/api/LayoutViewItem.h"
@@ skipping 1477 matching lines @@
       "    <div class='composited container'>"
       "      <div class='innerPadding'></div>"
       "      <div id='sticky' class='composited'></div>"
       "  </div></div></div>");
 
   PaintLayer* sticky_layer =
       ToLayoutBox(GetLayoutObjectByElementId("sticky"))->Layer();
   CompositedLayerMapping* sticky_mapping =
       sticky_layer->GetCompositedLayerMapping();
   ASSERT_TRUE(sticky_mapping);
-  // Main thread offset for sticky should be "StickyTop - InnerPadding".
-  EXPECT_EQ(IntPoint(0, 15), IntPoint(sticky_mapping->MainGraphicsLayer()
-                                          ->ContentLayer()
-                                          ->Layer()
-                                          ->OffsetForStickyPosition()));
 
   // Now scroll the page - this should increase the main thread offset.
   LayoutBoxModelObject* scroller =
       ToLayoutBoxModelObject(GetLayoutObjectByElementId("scroller"));
   PaintLayerScrollableArea* scrollable_area = scroller->GetScrollableArea();
   scrollable_area->ScrollToAbsolutePosition(
       FloatPoint(scrollable_area->ScrollPosition().X(), 100));
   ASSERT_EQ(100.0, scrollable_area->ScrollPosition().Y());
 
   sticky_layer->SetNeedsCompositingInputsUpdate();
   EXPECT_TRUE(sticky_layer->NeedsCompositingInputsUpdate());
   GetDocument().View()->UpdateLifecycleToCompositingCleanPlusScrolling();
   EXPECT_FALSE(sticky_layer->NeedsCompositingInputsUpdate());
-
-  EXPECT_EQ(IntPoint(0, 115), IntPoint(sticky_mapping->MainGraphicsLayer()
-                                           ->ContentLayer()
-                                           ->Layer()
-                                           ->OffsetForStickyPosition()));
 }
 
 TEST_P(CompositedLayerMappingTest, StickyPositionNotSquashed) {
   SetBodyInnerHTML(
       "<style>"
       "#scroller { overflow: auto; height: 200px; }"
       "#sticky1, #sticky2, #sticky3 {position: sticky; top: 0; width: 50px;"
       "    height: 50px; background: rgba(0, 128, 0, 0.5);}"
       "#sticky1 {backface-visibility: hidden;}"
       ".spacer {height: 2000px;}"
@@ skipping 23 matching lines @@
   GetDocument().View()->UpdateAllLifecyclePhases();
 
   // Now that sticky2 and sticky3 overlap sticky1 they will be promoted, but
   // they should not be squashed into the same layer because they scroll with
   // respect to each other.
   EXPECT_EQ(kPaintsIntoOwnBacking, sticky1->GetCompositingState());
   EXPECT_EQ(kPaintsIntoOwnBacking, sticky2->GetCompositingState());
   EXPECT_EQ(kPaintsIntoOwnBacking, sticky3->GetCompositingState());
 }
 
+TEST_P(CompositedLayerMappingTest,
+       LayerPositionForStickyElementInCompositedScroller) {
+  SetBodyInnerHTML(
+      "<style>"
+      " .scroller { overflow: scroll; width: 200px; height: 600px; }"
+      " .composited { will-change:transform; }"
+      " .box { position: sticky; width: 185px; height: 50px; top: 0px; }"
+      " .container { width: 100%; height: 1000px; }"
+      "</style>"
+      "<div id='scroller' class='composited scroller'>"
+      " <div class='container'>"
+      "  <div id='sticky' class='box'></div>"
+      " </div>"
+      "</div>");
+
+  CompositedLayerMapping* mapping =
+      ToLayoutBlock(GetLayoutObjectByElementId("sticky"))
+          ->Layer()
+          ->GetCompositedLayerMapping();
+  ASSERT_TRUE(mapping);
+  GraphicsLayer* main_graphics_layer = mapping->MainGraphicsLayer();
+
+  PaintLayer* scroller =
+      ToLayoutBlock(GetLayoutObjectByElementId("scroller"))->Layer();
+  PaintLayerScrollableArea* scrollable_area = scroller->GetScrollableArea();
+  scrollable_area->ScrollToAbsolutePosition(
+      FloatPoint(scrollable_area->ScrollPosition().Y(), 100));
+  GetDocument().View()->UpdateAllLifecyclePhases();
+
+  EXPECT_FLOAT_EQ(0, main_graphics_layer->GetPosition().X());
+  EXPECT_FLOAT_EQ(0, main_graphics_layer->GetPosition().Y());
+}
+
+TEST_P(CompositedLayerMappingTest,
+       LayerPositionForStickyElementInNonCompositedScroller) {
+  SetBodyInnerHTML(
+      "<style>"
+      " .scroller { overflow: scroll; width: 200px; height: 600px; }"
+      " .composited { will-change:transform; }"
+      " .box { position: sticky; width: 185px; height: 50px; top: 0px; }"
+      " .container { width: 100%; height: 1000px; }"
+      "</style>"
+      "<div id='scroller' class='scroller'>"
+      " <div class='composited container'>"

[flackr, 2017/06/09 17:33:33]

Add this above too so the cases are identical other than the composited
scroller.

[yigu, 2017/06/09 17:41:16]

Done.

+      "  <div id='sticky' class='box'></div>"
+      " </div>"
+      "</div>");
+
+  CompositedLayerMapping* mapping =
+      ToLayoutBlock(GetLayoutObjectByElementId("sticky"))
+          ->Layer()
+          ->GetCompositedLayerMapping();
+  ASSERT_TRUE(mapping);
+  GraphicsLayer* main_graphics_layer = mapping->MainGraphicsLayer();
+
+  PaintLayer* scroller =
+      ToLayoutBlock(GetLayoutObjectByElementId("scroller"))->Layer();
+  PaintLayerScrollableArea* scrollable_area = scroller->GetScrollableArea();
+  ASSERT_TRUE(scrollable_area);
+  scrollable_area->ScrollToAbsolutePosition(
+      FloatPoint(scrollable_area->ScrollPosition().Y(), 100));
+  GetDocument().View()->UpdateAllLifecyclePhases();
+
+  EXPECT_FLOAT_EQ(0, main_graphics_layer->GetPosition().X());
+  EXPECT_FLOAT_EQ(100, main_graphics_layer->GetPosition().Y());
+}
+
 }  // namespace blink