More accurate reasoning for non-opaque text blocking composited scrolling

Bug: 1074395
Change-Id: I6fb83b0466eb58fbcae1cfa15bc0b2a04dd642ac
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2212813
Commit-Queue: Xianzhu Wang <wangxianzhu@chromium.org>
Reviewed-by: Philip Rogers <pdr@chromium.org>
Cr-Commit-Position: refs/heads/master@{#771292}

cc/input/main_thread_scrolling_reason.cc

@@ -44,8 +44,8 @@ void MainThreadScrollingReason::AddToTracedValue(
     traced_value.AppendString("Handling scroll from main thread");
   if (reasons & kHasTransformAndLCDText)
     traced_value.AppendString("Has transform and LCD text");
-  if (reasons & kBackgroundNotOpaqueInRectAndLCDText)
-    traced_value.AppendString("Background is not opaque in rect and LCD text");
+  if (reasons & kNotOpaqueForTextAndLCDText)
+    traced_value.AppendString("Not opaque for text and LCD text");
   if (reasons & kCantPaintScrollingBackground)
     traced_value.AppendString("Can't paint scrolling background");
   if (reasons & kHasClipRelatedProperty)

cc/input/main_thread_scrolling_reason.h

@@ -44,7 +44,7 @@ struct CC_EXPORT MainThreadScrollingReason {
     // screen position; transparency and transforms break this.
     kNonCompositedReasonsFirst = 17,
     kHasTransformAndLCDText = 1 << 17,
-    kBackgroundNotOpaqueInRectAndLCDText = 1 << 18,
+    kNotOpaqueForTextAndLCDText = 1 << 18,
     kCantPaintScrollingBackground = 1 << 19,
     kHasClipRelatedProperty = 1 << 20,
     kNonCompositedReasonsLast = 22,
@@ -68,7 +68,7 @@ struct CC_EXPORT MainThreadScrollingReason {
   };
 
   static const uint32_t kNonCompositedReasons =
-      kHasTransformAndLCDText | kBackgroundNotOpaqueInRectAndLCDText |
+      kHasTransformAndLCDText | kNotOpaqueForTextAndLCDText |
       kCantPaintScrollingBackground | kHasClipRelatedProperty;
 
   // Returns true if the given MainThreadScrollingReason can be set by the main

cc/input/main_thread_scrolling_reason_unittest.cc

@@ -20,7 +20,7 @@ TEST_F(MainThreadScrollingReasonTest, AsText) {
       "Frame overlay, "
       "Handling scroll from main thread, "
       "Has transform and LCD text, "
-      "Background is not opaque in rect and LCD text, "
+      "Not opaque for text and LCD text, "
       "Can't paint scrolling background, "
       "Has clip related property, "
       "Non fast scrollable region, "

third_party/blink/renderer/core/page/scrolling/main_thread_scrolling_reasons_test.cc

@@ -299,7 +299,7 @@ class NonCompositedMainThreadScrollingReasonsTest
     : public MainThreadScrollingReasonsTest {
   static const uint32_t kLCDTextRelatedReasons =
       cc::MainThreadScrollingReason::kHasTransformAndLCDText |
-      cc::MainThreadScrollingReason::kBackgroundNotOpaqueInRectAndLCDText;
+      cc::MainThreadScrollingReason::kNotOpaqueForTextAndLCDText;
 
  protected:
   NonCompositedMainThreadScrollingReasonsTest() {
@@ -386,7 +386,7 @@ TEST_F(NonCompositedMainThreadScrollingReasonsTest, TransformTest) {
 TEST_F(NonCompositedMainThreadScrollingReasonsTest, BackgroundNotOpaqueTest) {
   TestNonCompositedReasons(
       "background-not-opaque",
-      cc::MainThreadScrollingReason::kBackgroundNotOpaqueInRectAndLCDText);
+      cc::MainThreadScrollingReason::kNotOpaqueForTextAndLCDText);
 }
 
 TEST_F(NonCompositedMainThreadScrollingReasonsTest,
@@ -456,8 +456,13 @@ TEST_F(NonCompositedMainThreadScrollingReasonsTest, StackingContextTest) {
                            cc::MainThreadScrollingReason::kNotScrollingOnMain);
 }
 
+TEST_F(NonCompositedMainThreadScrollingReasonsTest, BorderRadiusTest) {
+  TestNonCompositedReasons("border-radius",
+                           cc::MainThreadScrollingReason::kNotScrollingOnMain);
+}
+
 TEST_F(NonCompositedMainThreadScrollingReasonsTest,
-       CompositedWithLCDTextRelatedReasonsTest) {
+       ForcedComositingWithLCDRelatedReasons) {
   // With "will-change:transform" we composite elements with
   // LCDTextRelatedReasons only. For elements with other
   // NonCompositedReasons, we don't create scrollingLayer for their

third_party/blink/renderer/core/page/scrolling/scroll_metrics_test.cc

@@ -145,17 +145,17 @@ TEST_F(NonCompositedMainThreadScrollingReasonRecordTest,
   // Test touch scroll.
   Scroll(box, WebGestureDevice::kTouchscreen);
   EXPECT_TOUCH_BUCKET(kHasTransformAndLCDText, 1);
-  EXPECT_TOUCH_BUCKET(kBackgroundNotOpaqueInRectAndLCDText, 1);
+  EXPECT_TOUCH_BUCKET(kNotOpaqueForTextAndLCDText, 1);
 
   Scroll(box, WebGestureDevice::kTouchscreen);
   EXPECT_TOUCH_BUCKET(kHasTransformAndLCDText, 2);
-  EXPECT_TOUCH_BUCKET(kBackgroundNotOpaqueInRectAndLCDText, 2);
+  EXPECT_TOUCH_BUCKET(kNotOpaqueForTextAndLCDText, 2);
   EXPECT_TOUCH_TOTAL(4);
 
   // Test wheel scroll.
   Scroll(box, WebGestureDevice::kTouchpad);
   EXPECT_WHEEL_BUCKET(kHasTransformAndLCDText, 1);
-  EXPECT_WHEEL_BUCKET(kBackgroundNotOpaqueInRectAndLCDText, 1);
+  EXPECT_WHEEL_BUCKET(kNotOpaqueForTextAndLCDText, 1);
   EXPECT_WHEEL_TOTAL(2);
 }
 
@@ -182,7 +182,7 @@ TEST_F(NonCompositedMainThreadScrollingReasonRecordTest,
 
   Scroll(box, WebGestureDevice::kTouchpad);
   EXPECT_WHEEL_BUCKET(kHasTransformAndLCDText, 1);
-  EXPECT_WHEEL_BUCKET(kBackgroundNotOpaqueInRectAndLCDText, 1);
+  EXPECT_WHEEL_BUCKET(kNotOpaqueForTextAndLCDText, 1);
   EXPECT_WHEEL_TOTAL(2);
 
   box->setAttribute("class", "composited transform box");
@@ -192,7 +192,7 @@ TEST_F(NonCompositedMainThreadScrollingReasonRecordTest,
                    ->GetScrollableArea()
                    ->GetNonCompositedMainThreadScrollingReasons());
   EXPECT_WHEEL_BUCKET(kHasTransformAndLCDText, 1);
-  EXPECT_WHEEL_BUCKET(kBackgroundNotOpaqueInRectAndLCDText, 1);
+  EXPECT_WHEEL_BUCKET(kNotOpaqueForTextAndLCDText, 1);
   EXPECT_WHEEL_TOTAL(2);
 }
 
@@ -216,14 +216,14 @@ TEST_F(NonCompositedMainThreadScrollingReasonRecordTest,
 
   Scroll(box, WebGestureDevice::kTouchpad);
   EXPECT_WHEEL_BUCKET(kHasTransformAndLCDText, 1);
-  EXPECT_WHEEL_BUCKET(kBackgroundNotOpaqueInRectAndLCDText, 1);
+  EXPECT_WHEEL_BUCKET(kNotOpaqueForTextAndLCDText, 1);
   EXPECT_WHEEL_TOTAL(2);
 
   box->setAttribute("class", "hidden transform box");
   UpdateAllLifecyclePhases();
   Scroll(box, WebGestureDevice::kTouchpad);
   EXPECT_WHEEL_BUCKET(kHasTransformAndLCDText, 1);
-  EXPECT_WHEEL_BUCKET(kBackgroundNotOpaqueInRectAndLCDText, 1);
+  EXPECT_WHEEL_BUCKET(kNotOpaqueForTextAndLCDText, 1);
   EXPECT_WHEEL_TOTAL(2);
 }
 
@@ -258,7 +258,7 @@ TEST_F(NonCompositedMainThreadScrollingReasonRecordTest, NestedScrollersTest) {
   // Scrolling the inner box will gather reasons from the scrolling chain. The
   // inner box itself has no reason because it's composited. Other scrollable
   // areas from the chain have corresponding reasons.
-  EXPECT_WHEEL_BUCKET(kBackgroundNotOpaqueInRectAndLCDText, 1);
+  EXPECT_WHEEL_BUCKET(kNotOpaqueForTextAndLCDText, 1);
   EXPECT_WHEEL_BUCKET(kHasTransformAndLCDText, 0);
   EXPECT_WHEEL_TOTAL(1);
 }

third_party/blink/renderer/core/paint/paint_layer_scrollable_area.cc

@@ -2525,10 +2525,13 @@ bool PaintLayerScrollableArea::ComputeNeedsCompositedScrollingInternal(
           cc::MainThreadScrollingReason::kHasTransformAndLCDText;
       needs_composited_scrolling = false;
     }
-    if (!layer_->BackgroundIsKnownToBeOpaqueInRect(
-            box->PhysicalPaddingBoxRect(), true)) {
+    if (!box->TextIsKnownToBeOnOpaqueBackground() ||
+        // TODO(wangxianzhu): This is temporary to continue to disable
+        // composited scrolling by default for sub-LayoutViews. Will enable in a
+        // followup. See LayoutView::BackgroundIsKnownToBeOpaqueInRect().
+        (box->IsLayoutView() && !box->GetFrame()->IsMainFrame())) {
       non_composited_main_thread_scrolling_reasons_ |=
-          cc::MainThreadScrollingReason::kBackgroundNotOpaqueInRectAndLCDText;
+          cc::MainThreadScrollingReason::kNotOpaqueForTextAndLCDText;
       needs_composited_scrolling = false;
     }
     if (!(background_paint_location_if_composited &

third_party/blink/web_tests/FlagExpectations/composite-after-paint

@@ -93,3 +93,7 @@ crbug.com/1047359 http/tests/subresource_filter/ad-highlight-frame-resized.html
 
 compositing/gestures/gesture-tapHighlight-composited-img.html [ Pass Failure ]
 http/tests/images/image-decode-in-frame.html [ Pass Failure ]
+
+# Failures after crrev.com/c/2212813
+external/wpt/html/rendering/non-replaced-elements/the-fieldset-and-legend-elements/fieldset-overflow.html [ Crash ]
+fast/table/cell-percent-padding.html [ Crash ]

tools/metrics/histograms/enums.xml

@@ -42772,7 +42772,7 @@ from previous Chrome versions.
   <int value="16" label="Requires hit testing on custom scrollbars (obsolete)"/>
   <int value="17" label="Has opacity (obsolete)"/>
   <int value="18" label="Has transform"/>
-  <int value="19" label="Background not opaque in rect"/>
+  <int value="19" label="Not opaque for text"/>
   <int value="20" label="Can't paint scrolling background"/>
   <int value="21" label="Has clip related property"/>
   <int value="22" label="Has box shadow from non-root layer (obsolete)"/>