Re-collect graphics layers on change of frame throttling

Bug: 963782
Change-Id: I8c6faf984321c38765357bf613bdb27a71c282bb
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1616445Reviewed-by: Philip Rogers <pdr@chromium.org>
Commit-Queue: Xianzhu Wang <wangxianzhu@chromium.org>
Cr-Commit-Position: refs/heads/master@{#660846}

third_party/blink/renderer/core/frame/local_frame_view.cc

@@ -2357,7 +2357,7 @@ bool LocalFrameView::RunPrePaintLifecyclePhase(
       frame_view.SetNeedsPaintPropertyUpdate();
       // We may record more foreign layers under the frame.
       if (RuntimeEnabledFeatures::BlinkGenPropertyTreesEnabled())
-        frame_view.SetPaintArtifactCompositorNeedsUpdate();
+        frame_view.GraphicsLayersDidChange();
       if (auto* owner = frame_view.GetLayoutEmbeddedContent())
         owner->SetShouldCheckForPaintInvalidation();
     }
@@ -4016,6 +4016,10 @@ void LocalFrameView::RenderThrottlingStatusChanged() {
   DCHECK(!IsInPerformLayout());
   DCHECK(!frame_->GetDocument() || !frame_->GetDocument()->InStyleRecalc());
 
+  // We may record more/less foreign layers under the frame.
+  if (RuntimeEnabledFeatures::BlinkGenPropertyTreesEnabled())
+    GraphicsLayersDidChange();
+
   ScrollingCoordinator* scrolling_coordinator = this->GetScrollingCoordinator();
   if (!CanThrottleRendering()) {
     // ScrollingCoordinator needs to update according to the new throttling
@@ -4036,9 +4040,6 @@ void LocalFrameView::RenderThrottlingStatusChanged() {
       layout_view->AddSubtreePaintPropertyUpdateReason(
           SubtreePaintPropertyUpdateReason::kPreviouslySkipped);
     }
-    // We may record more foreign layers under the frame.
-    if (RuntimeEnabledFeatures::BlinkGenPropertyTreesEnabled())
-      SetPaintArtifactCompositorNeedsUpdate();
   }
 
   if (scrolling_coordinator) {

third_party/blink/renderer/core/frame/local_frame_view.h

@@ -991,6 +991,7 @@ class CORE_EXPORT LocalFrameView final
 #endif
 
   FRIEND_TEST_ALL_PREFIXES(WebViewTest, DeviceEmulationResetScrollbars);
+  FRIEND_TEST_ALL_PREFIXES(FrameThrottlingTest, GraphicsLayerCollection);
 };
 
 inline void LocalFrameView::IncrementVisuallyNonEmptyCharacterCount(

third_party/blink/renderer/core/scheduler/frame_throttling_test.cc

@@ -26,6 +26,7 @@
 #include "third_party/blink/renderer/core/testing/sim/sim_compositor.h"
 #include "third_party/blink/renderer/core/testing/sim/sim_request.h"
 #include "third_party/blink/renderer/core/testing/sim/sim_test.h"
+#include "third_party/blink/renderer/platform/graphics/paint/paint_controller.h"
 #include "third_party/blink/renderer/platform/graphics/paint/transform_paint_property_node.h"
 #include "third_party/blink/renderer/platform/testing/paint_test_configurations.h"
 #include "third_party/blink/renderer/platform/testing/unit_test_helpers.h"
@@ -1392,4 +1393,71 @@ TEST_P(FrameThrottlingTest, LifecycleUpdateAfterUnthrottledCompositingUpdate) {
   }
 }
 
+TEST_P(FrameThrottlingTest, GraphicsLayerCollection) {
+  // This test is for BlinkGenPropertyTrees only.
+  if (!RuntimeEnabledFeatures::BlinkGenPropertyTreesEnabled() ||
+      RuntimeEnabledFeatures::CompositeAfterPaintEnabled())
+    return;
+
+  SimRequest main_resource("https://example.com/", "text/html");
+  SimRequest frame_resource("https://example.com/iframe.html", "text/html");
+
+  LoadURL("https://example.com/");
+  // The frame is initially throttled.
+  main_resource.Complete(
+      "<iframe id='frame' sandbox src='iframe.html'></iframe>");
+  frame_resource.Complete(
+      "<div id='div' style='will-change: transform'>Foo</div>");
+
+  DocumentLifecycle::AllowThrottlingScope throttling_scope(
+      GetDocument().Lifecycle());
+  CompositeFrame();
+
+  auto* frame_element =
+      ToHTMLIFrameElement(GetDocument().getElementById("frame"));
+  auto* frame_document = frame_element->contentDocument();
+  EXPECT_FALSE(frame_document->View()->ShouldThrottleRendering());
+  auto* paint_controller = GetDocument().View()->GetPaintController();
+  ASSERT_NE(nullptr, paint_controller);
+  auto display_item_count = paint_controller->GetDisplayItemList().size();
+
+  // Moving the child fully outside the parent makes it invisible.
+  frame_element->setAttribute(kStyleAttr, "transform: translateY(480px)");
+  CompositeFrame();
+  EXPECT_TRUE(frame_document->View()->ShouldThrottleRendering());
+  // Change of throttling clears paint controller, to force re-collection of
+  // graphics layers in the next frame.
+  EXPECT_EQ(nullptr, GetDocument().View()->GetPaintController());
+
+  // Force a frame update. We should re-collect the graphics layers.
+  GetDocument().GetPage()->Animator().ScheduleVisualUpdate(
+      GetDocument().GetFrame());
+  CompositeFrame();
+  EXPECT_TRUE(frame_document->View()->ShouldThrottleRendering());
+  paint_controller = GetDocument().View()->GetPaintController();
+  ASSERT_NE(nullptr, paint_controller);
+  // We no longer collect the graphics layers of the iframe and the composited
+  // content.
+  EXPECT_EQ(display_item_count - 2,
+            paint_controller->GetDisplayItemList().size());
+
+  // Move the child back to the visible viewport.
+  frame_element->setAttribute(kStyleAttr,
+                              "transform: translate(-50px, 0px, 0px)");
+  // Update throttling, which will schedule visual update on unthrottling of the
+  // frame.
+  CompositeFrame();
+  EXPECT_FALSE(frame_document->View()->ShouldThrottleRendering());
+  // Change of throttling clears paint controller, to force re-collection of
+  // graphics layers in the next frame.
+  EXPECT_EQ(nullptr, GetDocument().View()->GetPaintController());
+
+  CompositeFrame();
+  EXPECT_FALSE(frame_document->View()->ShouldThrottleRendering());
+  paint_controller = GetDocument().View()->GetPaintController();
+  ASSERT_NE(nullptr, paint_controller);
+  // Now we should collect all graphics layers again.
+  EXPECT_EQ(display_item_count, paint_controller->GetDisplayItemList().size());
+}
+
 }  // namespace blink