Add UMAs for checking header values against RFC 7230 in //net

tools/metrics/histograms/histograms.xml

Index: tools/metrics/histograms/histograms.xml
diff --git a/tools/metrics/histograms/histograms.xml b/tools/metrics/histograms/histograms.xml
index 11757364db2b0e60deb5c6d2e11248057a6d6b48..aa1c6849158787613595293b12140d7873be1300 100644
--- a/tools/metrics/histograms/histograms.xml
+++ b/tools/metrics/histograms/histograms.xml
@@ -24274,6 +24274,15 @@ http://cs/file:chrome/histograms.xml - but prefer this file for new entries.
   <summary>Time it takes to request a new (unused) HTTP proxy socket.</summary>
 </histogram>
 
+<histogram name="Net.HttpRequest.ContainsInvalidHeaderValuesInRFC7230"
+    enum="Boolean">
+  <owner>hiroshige@chromium.org</owner>
+  <summary>
+    Whether a request contains invalid request header values in RFC 7230. This
+    is counted once for every redirect leg. https://crbug.com/455099.
+  </summary>
+</histogram>
+
 <histogram name="Net.HttpRequestCompletionErrorCodes" enum="NetErrorCodes">
   <owner>sclittle@chromium.org</owner>
   <owner>bengr@chromium.org</owner>
@@ -24293,6 +24302,15 @@ http://cs/file:chrome/histograms.xml - but prefer this file for new entries.
   </summary>
 </histogram>
 
+<histogram name="Net.HttpResponse.ContainsInvalidHeaderValuesInRFC7230"
+    enum="Boolean">
+  <owner>hiroshige@chromium.org</owner>
+  <summary>
+    Whether a response contains invalid response header values in RFC 7230. This
+    is counted once for every redirect leg. https://crbug.com/455099.
+  </summary>
+</histogram>
+
 <histogram name="Net.HttpResponseCode">
   <owner>mmenke@chromium.org</owner>
   <summary>The count of HTTP Response codes encountered.</summary>