ContentVisibility: Add UseCounters for each value (except visible).

This patch adds a use counter for each value of content visibility
other than the default.

R=chrishtr@chromium.org

Fixed: 1096676
Change-Id: I71dcb549b04b249f701bcc0b5b68f966052f0c8e
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2257540
Commit-Queue: vmpstr <vmpstr@chromium.org>
Auto-Submit: vmpstr <vmpstr@chromium.org>
Reviewed-by: Chris Harrelson <chrishtr@chromium.org>
Cr-Commit-Position: refs/heads/master@{#781372}

third_party/blink/public/mojom/web_feature/web_feature.mojom

@@ -2666,6 +2666,9 @@ enum WebFeature {
   kDialogWithNonZeroScrollOffset = 3329,
   kDialogHeightLargerThanViewport = 3330,
   kOverlayPopup = 3331,
+  kContentVisibilityAuto = 3332,
+  kContentVisibilityHidden = 3333,
+  kContentVisibilityHiddenMatchable = 3334,
 
   // Add new features immediately above this line. Don't change assigned
   // numbers of any item, and don't reuse removed slots.

third_party/blink/renderer/core/display_lock/display_lock_context.cc

@@ -29,6 +29,7 @@
 #include "third_party/blink/renderer/core/paint/pre_paint_tree_walk.h"
 #include "third_party/blink/renderer/platform/bindings/microtask.h"
 #include "third_party/blink/renderer/platform/heap/heap.h"
+#include "third_party/blink/renderer/platform/instrumentation/use_counter.h"
 
 namespace blink {
 
@@ -105,12 +106,16 @@ void DisplayLockContext::SetRequestedState(EContentVisibility state) {
       RequestUnlock();
       break;
     case EContentVisibility::kAuto:
+      UseCounter::Count(document_, WebFeature::kContentVisibilityAuto);
       RequestLock(static_cast<uint16_t>(DisplayLockActivationReason::kAny));
       break;
     case EContentVisibility::kHidden:
+      UseCounter::Count(document_, WebFeature::kContentVisibilityHidden);
       RequestLock(0u);
       break;
     case EContentVisibility::kHiddenMatchable:
+      UseCounter::Count(document_,
+                        WebFeature::kContentVisibilityHiddenMatchable);
       RequestLock(
           static_cast<uint16_t>(DisplayLockActivationReason::kAny) &
           ~static_cast<uint16_t>(DisplayLockActivationReason::kViewport));

third_party/blink/renderer/core/display_lock/display_lock_context_test.cc

@@ -2493,6 +2493,50 @@ TEST_F(DisplayLockContextRenderingTest, ContainStrictChild) {
   UpdateAllLifecyclePhasesForTest();
 }
 
+TEST_F(DisplayLockContextRenderingTest, UseCounter) {
+  SetHtmlInnerHTML(R"HTML(
+    <style>
+      .auto { content-visibility: auto; }
+      .hidden { content-visibility: hidden; }
+      .matchable { content-visibility: hidden-matchable; }
+    </style>
+    <div id=e1></div>
+    <div id=e2></div>
+    <div id=e3></div>
+  )HTML");
+
+  EXPECT_FALSE(GetDocument().IsUseCounted(WebFeature::kContentVisibilityAuto));
+  EXPECT_FALSE(
+      GetDocument().IsUseCounted(WebFeature::kContentVisibilityHidden));
+  EXPECT_FALSE(GetDocument().IsUseCounted(
+      WebFeature::kContentVisibilityHiddenMatchable));
+
+  GetDocument().getElementById("e1")->classList().Add("auto");
+  UpdateAllLifecyclePhasesForTest();
+
+  EXPECT_TRUE(GetDocument().IsUseCounted(WebFeature::kContentVisibilityAuto));
+  EXPECT_FALSE(
+      GetDocument().IsUseCounted(WebFeature::kContentVisibilityHidden));
+  EXPECT_FALSE(GetDocument().IsUseCounted(
+      WebFeature::kContentVisibilityHiddenMatchable));
+
+  GetDocument().getElementById("e2")->classList().Add("hidden");
+  UpdateAllLifecyclePhasesForTest();
+
+  EXPECT_TRUE(GetDocument().IsUseCounted(WebFeature::kContentVisibilityAuto));
+  EXPECT_TRUE(GetDocument().IsUseCounted(WebFeature::kContentVisibilityHidden));
+  EXPECT_FALSE(GetDocument().IsUseCounted(
+      WebFeature::kContentVisibilityHiddenMatchable));
+
+  GetDocument().getElementById("e3")->classList().Add("matchable");
+  UpdateAllLifecyclePhasesForTest();
+
+  EXPECT_TRUE(GetDocument().IsUseCounted(WebFeature::kContentVisibilityAuto));
+  EXPECT_TRUE(GetDocument().IsUseCounted(WebFeature::kContentVisibilityHidden));
+  EXPECT_TRUE(GetDocument().IsUseCounted(
+      WebFeature::kContentVisibilityHiddenMatchable));
+}
+
 TEST_F(DisplayLockContextRenderingTest, CompositingRootIsSkippedIfLocked) {
   SetHtmlInnerHTML(R"HTML(
     <style>

tools/metrics/histograms/enums.xml

@@ -28069,6 +28069,9 @@ Called by update_use_counter_feature_enum.py.-->
   <int value="3329" label="DialogWithNonZeroScrollOffset"/>
   <int value="3330" label="DialogHeightLargerThanViewport"/>
   <int value="3331" label="OverlayPopup"/>
+  <int value="3332" label="ContentVisibilityAuto"/>
+  <int value="3333" label="ContentVisibilityHidden"/>
+  <int value="3334" label="ContentVisibilityHiddenMatchable"/>
 </enum>
 
 <enum name="FeaturePolicyAllowlistType">