Enable HitTestCache by default.

Source/core/layout/HitTestCache.cpp

Index: Source/core/layout/HitTestCache.cpp
diff --git a/Source/core/layout/HitTestCache.cpp b/Source/core/layout/HitTestCache.cpp
index 8ab3377278f84a396d7067cc8e9b4174c35650ab..4c6fbe1512a6a881b529178e0887ac1e94158674 100644
--- a/Source/core/layout/HitTestCache.cpp
+++ b/Source/core/layout/HitTestCache.cpp
@@ -33,21 +33,6 @@ bool HitTestCache::lookupCachedResult(HitTestResult& hitResult, uint64_t domTree
     return result;
 }
 
-void HitTestCache::verifyCachedResult(const HitTestResult& expected, const HitTestResult& actual)
-{
-    ValidityHistogramMetric metric;
-    if (!actual.equalForCacheability(expected)) {
-        metric = expected.hitTestLocation().isRectBasedTest() ? ValidityHistogramMetric::INCORRECT_RECT_BASED_EXACT_MATCH : ValidityHistogramMetric::INCORRECT_POINT_EXACT_MATCH;
-        Platform::current()->histogramSparse("Event.HitTestValidityScore", static_cast<int>(actual.equalityScore(expected)));
-
-        // ASSERT that the cache hit is the same as the actual result.
-        ASSERT_NOT_REACHED();
-    } else {
-        metric = ValidityHistogramMetric::VALID_EXACT_MATCH;
-    }
-    Platform::current()->histogramEnumeration("Event.HitTestValidity", static_cast<int>(metric), static_cast<int>(ValidityHistogramMetric::MAX_VALIDITY_METRIC));
-}
-
 void HitTestCache::addCachedResult(const HitTestResult& result, uint64_t domTreeVersion)
 {
     if (!result.isCacheable())