Add use counters for :focus and :focus-visible.

The goal of this change is to track developer uptake of :focus-visible,
once it ships from behind a flag. We also want to monitor the usage
of :focus. This data will help us explore possibly switching the UA stylesheet
over to using :focus-visible someday.


R=aboxhall@chromium.org

Bug: 817199
Change-Id: I257ab590f03d28831ec517b67f42e6f86a156ee9
Reviewed-on: https://chromium-review.googlesource.com/954102Reviewed-by: Kent Tamura <tkent@chromium.org>
Reviewed-by: Takayoshi Kochi <kochi@chromium.org>
Reviewed-by: Luna Lu <loonybear@chromium.org>
Reviewed-by: Rick Byers <rbyers@chromium.org>
Commit-Queue: Rob Dodson <robdodson@chromium.org>
Cr-Commit-Position: refs/heads/master@{#542279}

third_party/WebKit/Source/core/css/parser/CSSSelectorParser.cpp

@@ -945,6 +945,15 @@ void CSSSelectorParser::RecordUsageAndDeprecations(
           DCHECK(RuntimeEnabledFeatures::CSSMatchesEnabled());
           feature = WebFeature::kCSSSelectorPseudoMatches;
           break;
+        case CSSSelector::kPseudoFocusVisible:
+          DCHECK(RuntimeEnabledFeatures::CSSFocusVisibleEnabled());
+          if (context_->Mode() != kUASheetMode)
+            feature = WebFeature::kCSSSelectorPseudoFocusVisible;
+          break;
+        case CSSSelector::kPseudoFocus:
+          if (context_->Mode() != kUASheetMode)
+            feature = WebFeature::kCSSSelectorPseudoFocus;
+          break;
         case CSSSelector::kPseudoAnyLink:
           feature = WebFeature::kCSSSelectorPseudoAnyLink;
           break;

third_party/WebKit/Source/core/frame/UseCounterTest.cpp

@@ -249,47 +249,6 @@ TEST_F(UseCounterTest, SVGImageContextAnimatedCSSProperties) {
       [&](LocalFrame* frame) { use_counter.DidCommitLoad(frame); }, kSvgUrl);
 }
 
-TEST_F(UseCounterTest, CSSSelectorPseudoAnyLink) {
-  std::unique_ptr<DummyPageHolder> dummy_page_holder =
-      DummyPageHolder::Create(IntSize(800, 600));
-  Document& document = dummy_page_holder->GetDocument();
-  WebFeature feature = WebFeature::kCSSSelectorPseudoAnyLink;
-  EXPECT_FALSE(UseCounter::IsCounted(document, feature));
-  document.documentElement()->SetInnerHTMLFromString(
-      "<style>:any-link { color: red; }</style>");
-  EXPECT_TRUE(UseCounter::IsCounted(document, feature));
-}
-
-TEST_F(UseCounterTest, CSSSelectorPseudoWebkitAnyLink) {
-  std::unique_ptr<DummyPageHolder> dummy_page_holder =
-      DummyPageHolder::Create(IntSize(800, 600));
-  Document& document = dummy_page_holder->GetDocument();
-  WebFeature feature = WebFeature::kCSSSelectorPseudoWebkitAnyLink;
-  EXPECT_FALSE(UseCounter::IsCounted(document, feature));
-  document.documentElement()->SetInnerHTMLFromString(
-      "<style>:-webkit-any-link { color: red; }</style>");
-  EXPECT_TRUE(UseCounter::IsCounted(document, feature));
-}
-
-TEST_F(UseCounterTest, CSSTypedOMStylePropertyMap) {
-  UseCounter use_counter;
-  WebFeature feature = WebFeature::kCSSTypedOMStylePropertyMap;
-  EXPECT_FALSE(use_counter.IsCounted(GetDocument(), feature));
-  use_counter.Count(GetDocument(), feature);
-  EXPECT_TRUE(use_counter.IsCounted(GetDocument(), feature));
-}
-
-TEST_F(UseCounterTest, CSSSelectorPseudoMatches) {
-  std::unique_ptr<DummyPageHolder> dummy_page_holder =
-      DummyPageHolder::Create(IntSize(800, 600));
-  Document& document = dummy_page_holder->GetDocument();
-  WebFeature feature = WebFeature::kCSSSelectorPseudoMatches;
-  EXPECT_FALSE(UseCounter::IsCounted(document, feature));
-  document.documentElement()->SetInnerHTMLFromString(
-      "<style>.a+:matches(.b, .c+.d) { color: red; }</style>");
-  EXPECT_TRUE(UseCounter::IsCounted(document, feature));
-}
-
 TEST_F(UseCounterTest, InspectorDisablesMeasurement) {
   UseCounter use_counter;
 
@@ -336,6 +295,58 @@ TEST_F(UseCounterTest, InspectorDisablesMeasurement) {
       UseCounter::MapCSSPropertyIdToCSSSampleIdForHistogram(property), 1);
 }
 
+/*
+ * Counter-specific tests
+ *
+ * NOTE: Most individual UseCounters don't need dedicated test cases.  They are
+ * "tested" by analyzing the data they generate including on some known pages.
+ * Feel free to add tests for counters where the triggering logic is
+ * non-trivial, but it's not required. Manual analysis is necessary to trust the
+ * data anyway, real-world pages are full of edge-cases and surprises that you
+ * won't find in unit testing anyway.
+ */
+
+TEST_F(UseCounterTest, CSSSelectorPseudoAnyLink) {
+  std::unique_ptr<DummyPageHolder> dummy_page_holder =
+      DummyPageHolder::Create(IntSize(800, 600));
+  Document& document = dummy_page_holder->GetDocument();
+  WebFeature feature = WebFeature::kCSSSelectorPseudoAnyLink;
+  EXPECT_FALSE(UseCounter::IsCounted(document, feature));
+  document.documentElement()->SetInnerHTMLFromString(
+      "<style>:any-link { color: red; }</style>");
+  EXPECT_TRUE(UseCounter::IsCounted(document, feature));
+}
+
+TEST_F(UseCounterTest, CSSSelectorPseudoWebkitAnyLink) {
+  std::unique_ptr<DummyPageHolder> dummy_page_holder =
+      DummyPageHolder::Create(IntSize(800, 600));
+  Document& document = dummy_page_holder->GetDocument();
+  WebFeature feature = WebFeature::kCSSSelectorPseudoWebkitAnyLink;
+  EXPECT_FALSE(UseCounter::IsCounted(document, feature));
+  document.documentElement()->SetInnerHTMLFromString(
+      "<style>:-webkit-any-link { color: red; }</style>");
+  EXPECT_TRUE(UseCounter::IsCounted(document, feature));
+}
+
+TEST_F(UseCounterTest, CSSTypedOMStylePropertyMap) {
+  UseCounter use_counter;
+  WebFeature feature = WebFeature::kCSSTypedOMStylePropertyMap;
+  EXPECT_FALSE(use_counter.IsCounted(GetDocument(), feature));
+  use_counter.Count(GetDocument(), feature);
+  EXPECT_TRUE(use_counter.IsCounted(GetDocument(), feature));
+}
+
+TEST_F(UseCounterTest, CSSSelectorPseudoMatches) {
+  std::unique_ptr<DummyPageHolder> dummy_page_holder =
+      DummyPageHolder::Create(IntSize(800, 600));
+  Document& document = dummy_page_holder->GetDocument();
+  WebFeature feature = WebFeature::kCSSSelectorPseudoMatches;
+  EXPECT_FALSE(UseCounter::IsCounted(document, feature));
+  document.documentElement()->SetInnerHTMLFromString(
+      "<style>.a+:matches(.b, .c+.d) { color: red; }</style>");
+  EXPECT_TRUE(UseCounter::IsCounted(document, feature));
+}
+
 TEST_F(UseCounterTest, DropMeasurementOnViewSourcePages) {
   UseCounter use_counter;
   SetIsViewSource();

third_party/WebKit/public/platform/web_feature.mojom

@@ -1876,6 +1876,8 @@ enum WebFeature {
   kRtcPeerConnectionId = 2384,
   kV8PaintWorkletGlobalScope_RegisterPaint_Method = 2385,
   kV8PaintWorkletGlobalScope_DevicePixelRatio_AttributeGetter = 2386,
+  kCSSSelectorPseudoFocus = 2387,
+  kCSSSelectorPseudoFocusVisible = 2388,
 
   // Add new features immediately above this line. Don't change assigned
   // numbers of any item, and don't reuse removed slots.

tools/metrics/histograms/enums.xml

@@ -17943,6 +17943,8 @@ Called by update_net_error_codes.py.-->
   <int value="2385" label="V8PaintWorkletGlobalScope_RegisterPaint_Method"/>
   <int value="2386"
       label="V8PaintWorkletGlobalScope_DevicePixelRatio_AttributeGetter"/>
+  <int value="2387" label="CSSSelectorPseudoFocus"/>
+  <int value="2388" label="CSSSelectorPseudoFocusVisible"/>
 </enum>
 
 <enum name="FeedbackSource">
@@ -27862,9 +27864,9 @@ Called by update_use_counter_css.py.-->
   <int value="175" label="webkit-appearance"/>
   <int value="176" label="webkit-aspect-ratio"/>
   <int value="177" label="alias-webkit-backface-visibility"/>
-  <int value="178" label="webkit-background-clip"/>
+  <int value="178" label="alias-webkit-background-clip"/>
   <int value="179" label="webkit-background-composite"/>
-  <int value="180" label="webkit-background-origin"/>
+  <int value="180" label="alias-webkit-background-origin"/>
   <int value="181" label="alias-webkit-background-size"/>
   <int value="182" label="webkit-border-after"/>
   <int value="183" label="webkit-border-after-color"/>
@@ -28275,6 +28277,8 @@ Called by update_use_counter_css.py.-->
   <int value="588" label="font-variant-east-asian"/>
   <int value="589" label="text-decoration-skip-ink"/>
   <int value="590" label="scroll-customization"/>
+  <int value="591" label="row-gap"/>
+  <int value="592" label="gap"/>
 </enum>
 
 <enum name="MappedEditingCommands">