Don't report first contentful paint when painting opacity:0

Move IgnorePaintTimingScope from paint_timing_detector.h into dedicated
.h and .cc files under renderer/platform, so that PaintController can
check it before recording first paint status.

This fixes several wpt tests for FCP about opacity in
CompositeAfterPaint which always paint opacity:0 contents. This doesn't
fix (and probably we'll never fix) missing FCP when opacity:0 becomes
non-zero, because we don't repaint.

Change-Id: If1b393f5c1440fada11806a7ac071b5700843ac5
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2145134
Commit-Queue: Xianzhu Wang <wangxianzhu@chromium.org>
Reviewed-by: Philip Rogers <pdr@chromium.org>
Cr-Commit-Position: refs/heads/master@{#758350}

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

@@ -63,8 +63,6 @@ bool IsBackgroundImageContentful(const LayoutObject& object,
 
 }  // namespace
 
-bool IgnorePaintTimingScope::should_ignore_ = false;
-
 PaintTimingDetector::PaintTimingDetector(LocalFrameView* frame_view)
     : frame_view_(frame_view),
       text_paint_timing_detector_(

third_party/blink/renderer/core/paint/paint_timing_detector.h

@@ -11,6 +11,7 @@
 #include "third_party/blink/renderer/core/layout/layout_box_model_object.h"
 #include "third_party/blink/renderer/core/paint/paint_timing_visualizer.h"
 #include "third_party/blink/renderer/core/scroll/scroll_types.h"
+#include "third_party/blink/renderer/platform/graphics/paint/ignore_paint_timing_scope.h"
 #include "third_party/blink/renderer/platform/heap/member.h"
 #include "third_party/blink/renderer/platform/wtf/cross_thread_functional.h"
 
@@ -273,22 +274,6 @@ class ScopedPaintTimingDetectorBlockPaintHook {
   DISALLOW_COPY_AND_ASSIGN(ScopedPaintTimingDetectorBlockPaintHook);
 };
 
-// Creates a scope to ignore paint timing, e.g. when we are painting contents
-// under opacity:0.
-class IgnorePaintTimingScope {
-  STACK_ALLOCATED();
-
- public:
-  IgnorePaintTimingScope() : auto_reset_(&should_ignore_, true) {}
-  ~IgnorePaintTimingScope() = default;
-
-  static bool ShouldIgnore() { return should_ignore_; }
-
- private:
-  base::AutoReset<bool> auto_reset_;
-  static bool should_ignore_;
-};
-
 // static
 inline void PaintTimingDetector::NotifyTextPaint(
     const IntRect& text_visual_rect) {

third_party/blink/renderer/platform/BUILD.gn

@@ -1041,6 +1041,8 @@ jumbo_component("platform") {
     "graphics/paint/graphics_layer_display_item.h",
     "graphics/paint/hit_test_data.cc",
     "graphics/paint/hit_test_data.h",
+    "graphics/paint/ignore_paint_timing_scope.cc",
+    "graphics/paint/ignore_paint_timing_scope.h",
     "graphics/paint/paint_artifact.cc",
     "graphics/paint/paint_artifact.h",
     "graphics/paint/paint_canvas.h",

third_party/blink/renderer/platform/graphics/paint/ignore_paint_timing_scope.cc

+// Copyright 2020 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 "third_party/blink/renderer/platform/graphics/paint/ignore_paint_timing_scope.h"
+
+namespace blink {
+
+bool IgnorePaintTimingScope::should_ignore_ = false;
+
+}  // namespace blink

third_party/blink/renderer/platform/graphics/paint/ignore_paint_timing_scope.h

+// Copyright 2020 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.
+
+#ifndef THIRD_PARTY_BLINK_RENDERER_PLATFORM_GRAPHICS_PAINT_IGNORE_PAINT_TIMING_SCOPE_H_
+#define THIRD_PARTY_BLINK_RENDERER_PLATFORM_GRAPHICS_PAINT_IGNORE_PAINT_TIMING_SCOPE_H_
+
+#include "base/auto_reset.h"
+#include "third_party/blink/renderer/platform/platform_export.h"
+#include "third_party/blink/renderer/platform/wtf/allocator/allocator.h"
+
+namespace blink {
+
+// Creates a scope to ignore paint timing, e.g. when we are painting contents
+// under opacity:0.
+class PLATFORM_EXPORT IgnorePaintTimingScope {
+  STACK_ALLOCATED();
+
+ public:
+  IgnorePaintTimingScope() : auto_reset_(&should_ignore_, true) {}
+  ~IgnorePaintTimingScope() = default;
+
+  static bool ShouldIgnore() { return should_ignore_; }
+
+ private:
+  base::AutoReset<bool> auto_reset_;
+  static bool should_ignore_;
+};
+
+}  // namespace blink
+
+#endif  // THIRD_PARTY_BLINK_RENDERER_PLATFORM_GRAPHICS_PAINT_IGNORE_PAINT_TIMING_SCOPE_H_

third_party/blink/renderer/platform/graphics/paint/paint_controller.cc

@@ -9,6 +9,7 @@
 #include "base/metrics/histogram_macros.h"
 #include "third_party/blink/renderer/platform/graphics/logging_canvas.h"
 #include "third_party/blink/renderer/platform/graphics/paint/drawing_display_item.h"
+#include "third_party/blink/renderer/platform/graphics/paint/ignore_paint_timing_scope.h"
 #include "third_party/blink/renderer/platform/instrumentation/tracing/trace_event.h"
 
 namespace blink {
@@ -794,14 +795,17 @@ void PaintController::CheckUnderInvalidation() {
 }
 
 void PaintController::SetFirstPainted() {
+  if (!IgnorePaintTimingScope::ShouldIgnore())
     frame_first_paints_.back().first_painted = true;
 }
 
 void PaintController::SetTextPainted() {
+  if (!IgnorePaintTimingScope::ShouldIgnore())
     frame_first_paints_.back().text_painted = true;
 }
 
 void PaintController::SetImagePainted() {
+  if (!IgnorePaintTimingScope::ShouldIgnore())
     frame_first_paints_.back().image_painted = true;
 }
 

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

@@ -30,6 +30,11 @@ compositing/overflow/scrolls-with-respect-to-nested.html [ Skip ]
 compositing/overflow/scrolls-with-respect-to-transform.html [ Skip ]
 compositing/overflow/scrolls-with-respect-to.html [ Skip ]
 
+# We don't repaint when opacity changes from zero to non-zero, so it's not feasible
+# to detect that as a first paint. Won't fix.
+external/wpt/paint-timing/fcp-only/fcp-opacity.html [ Skip ]
+external/wpt/paint-timing/fcp-only/fcp-pseudo-element-opacity.html [ Skip ]
+
 # Can't rebaseline because the file path is too long.
 virtual/compositor_threaded_scrollbar_scrolling/paint/invalidation/scroll/sticky/invalidate-after-composited-scroll-with-sticky.html [ Skip ]
 
@@ -109,8 +114,3 @@ crbug.com/1041322 virtual/threaded/synthetic_gestures/synthetic-pinch-zoom-gestu
 
 compositing/gestures/gesture-tapHighlight-composited-img.html [ Pass Failure ]
 http/tests/images/image-decode-in-frame.html [ Pass Failure ]
-
-crbug.com/1062984 external/wpt/paint-timing/fcp-only/fcp-opacity-descendant.html [ Failure ]
-crbug.com/1062984 external/wpt/paint-timing/fcp-only/fcp-opacity.html [ Failure ]
-crbug.com/1062984 external/wpt/paint-timing/fcp-only/fcp-pseudo-element-opacity.html [ Failure ]
-crbug.com/1062984 external/wpt/paint-timing/fcp-only/fcp-typographic-pseudo.html [ Failure ]