add use counter for resize with auto value

recent versions of the spec do not support 'auto' value.
so before retire that value, we should check how many use it.

Bug: 831550
Change-Id: I3b551ea759d05cade1e8823f3dc1c68f30b65816
Reviewed-on: https://chromium-review.googlesource.com/1007294
Commit-Queue: Hwanseung Lee <hwanseung@chromium.org>
Reviewed-by: Kentaro Hara <haraken@chromium.org>
Reviewed-by: Eric Willigers <ericwilligers@chromium.org>
Cr-Commit-Position: refs/heads/master@{#550166}

third_party/blink/public/platform/web_feature.mojom

@@ -1907,6 +1907,7 @@ enum WebFeature {
   kXRRequestSession = 2415,
   kXRSupportsSession = 2416,
   kXRSessionGetInputSources = 2417,
+  kCSSResizeAuto = 2418,
 
   // 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/css/resolver/style_builder_custom.cc

@@ -68,6 +68,8 @@
 #include "third_party/blink/renderer/core/css_value_keywords.h"
 #include "third_party/blink/renderer/core/frame/local_frame.h"
 #include "third_party/blink/renderer/core/frame/settings.h"
+#include "third_party/blink/renderer/core/frame/use_counter.h"
+#include "third_party/blink/renderer/core/frame/web_feature.h"
 #include "third_party/blink/renderer/core/style/computed_style.h"
 #include "third_party/blink/renderer/core/style/computed_style_constants.h"
 #include "third_party/blink/renderer/core/style/content_data.h"
@@ -373,6 +375,7 @@ void StyleBuilderFunctions::applyValueCSSPropertyResize(
       r = settings->GetTextAreasAreResizable() ? EResize::kBoth
                                                : EResize::kNone;
     }
+    UseCounter::Count(state.GetDocument(), WebFeature::kCSSResizeAuto);
   } else {
     r = identifier_value.ConvertTo<EResize>();
   }

tools/metrics/histograms/enums.xml

@@ -18270,6 +18270,7 @@ Called by update_net_error_codes.py.-->
   <int value="2415" label="XRRequestSession"/>
   <int value="2416" label="XRSupportsSession"/>
   <int value="2417" label="XRSessionGetInputSources"/>
+  <int value="2418" label="CSSResizeAuto"/>
 </enum>
 
 <enum name="FeedbackSource">