Implement support for the 'transform-box' property

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

Index: third_party/WebKit/Source/core/frame/UseCounter.cpp
diff --git a/third_party/WebKit/Source/core/frame/UseCounter.cpp b/third_party/WebKit/Source/core/frame/UseCounter.cpp
index 3e040c9c2a17dcd243e26c3ad6ee7cd80d43c7f5..dabb66f36ad08661adc5545c4c7467e324feb7bd 100644
--- a/third_party/WebKit/Source/core/frame/UseCounter.cpp
+++ b/third_party/WebKit/Source/core/frame/UseCounter.cpp
@@ -46,7 +46,7 @@ int totalPagesMeasuredCSSSampleId() {
 }
 
 // Make sure update_use_counter_css.py was run which updates histograms.xml.
-constexpr int kMaximumCSSSampleId = 557;
+constexpr int kMaximumCSSSampleId = 558;
 
 }  // namespace
 
@@ -1083,6 +1083,8 @@ int UseCounter::mapCSSPropertyIdToCSSSampleIdForHistogram(
       return 556;
     case CSSPropertyPlaceContent:
       return 557;
+    case CSSPropertyTransformBox:
+      return 558;
     // 1. Add new features above this line (don't change the assigned numbers of
     // the existing items).
     // 2. Update kMaximumCSSSampleId with the new maximum value.