Add use counters for signature-based SRI.

Add use counter to support an upcoming origin trial. Count how many signatures
are being checked, and how many of those were checked successfully.

Change-Id: I12fdeb9e4c3444d2920ff87d6fff681c98eba40b
Reviewed-on: https://chromium-review.googlesource.com/883804
Commit-Queue: Daniel Vogelheim <vogelheim@chromium.org>
Reviewed-by: Mike West <mkwst@chromium.org>
Cr-Commit-Position: refs/heads/master@{#532830}

third_party/WebKit/Source/core/loader/SubresourceIntegrityHelper.cpp

@@ -25,6 +25,12 @@ WebFeature GetWebFeature(
     case SubresourceIntegrity::ReportInfo::UseCounterFeature::
         kSRIElementWithUnparsableIntegrityAttribute:
       return WebFeature::kSRIElementWithUnparsableIntegrityAttribute;
+    case SubresourceIntegrity::ReportInfo::UseCounterFeature::
+        kSRISignatureCheck:
+      return WebFeature::kSRISignatureCheck;
+    case SubresourceIntegrity::ReportInfo::UseCounterFeature::
+        kSRISignatureSuccess:
+      return WebFeature::kSRISignatureSuccess;
   }
   NOTREACHED();
   return WebFeature::kSRIElementWithUnparsableIntegrityAttribute;

third_party/WebKit/Source/platform/loader/SubresourceIntegrity.cpp

@@ -149,11 +149,19 @@ bool SubresourceIntegrity::CheckSubresourceIntegrityImpl(
   // Check any of the "strongest" integrity constraints.
   IntegrityAlgorithm max_algorithm = FindBestAlgorithm(metadata_set);
   CheckFunction checker = GetCheckFunctionForAlgorithm(max_algorithm);
+  bool report_ed25519 = max_algorithm == IntegrityAlgorithm::kEd25519;
+  if (report_ed25519) {
+    report_info.AddUseCount(ReportInfo::UseCounterFeature::kSRISignatureCheck);
+  }
   for (const IntegrityMetadata& metadata : metadata_set) {
     if (metadata.Algorithm() == max_algorithm &&
         (*checker)(metadata, content, size, integrity_header)) {
       report_info.AddUseCount(ReportInfo::UseCounterFeature::
                                   kSRIElementWithMatchingIntegrityAttribute);
+      if (report_ed25519) {
+        report_info.AddUseCount(
+            ReportInfo::UseCounterFeature::kSRISignatureSuccess);
+      }
       return true;
     }
   }

third_party/WebKit/Source/platform/loader/SubresourceIntegrity.h

@@ -28,6 +28,8 @@ class PLATFORM_EXPORT SubresourceIntegrity final {
       kSRIElementWithNonMatchingIntegrityAttribute,
       kSRIElementIntegrityAttributeButIneligible,
       kSRIElementWithUnparsableIntegrityAttribute,
+      kSRISignatureCheck,
+      kSRISignatureSuccess,
     };
 
     void AddUseCount(UseCounterFeature);

third_party/WebKit/public/platform/web_feature.mojom

@@ -1862,6 +1862,8 @@ enum WebFeature {
   kV8HTMLElement_Autocapitalize_AttributeGetter = 2349,
   kV8HTMLElement_Autocapitalize_AttributeSetter = 2350,
   kCSSLegacyAlignment = 2351,
+  kSRISignatureCheck = 2352,
+  kSRISignatureSuccess = 2353,
 
   // Add new features immediately above this line. Don't change assigned
   // numbers of any item, and don't reuse removed slots.

tools/metrics/histograms/enums.xml

@@ -17581,8 +17581,7 @@ Called by update_net_error_codes.py.-->
   <int value="2228" label="DocumentPageShowRegistered"/>
   <int value="2229" label="DocumentPageShowFired"/>
   <int value="2230" label="ReplaceCharsetInXHR"/>
-  <int value="2231"
-      label="RespondToSameOriginRequestWithCrossOriginResponse (obsolete)"/>
+  <int value="2231" label="RespondToSameOriginRequestWithCrossOriginResponse"/>
   <int value="2232" label="LinkRelModulePreload"/>
   <int value="2233" label="PerformanceMeasurePassedInObject"/>
   <int value="2234" label="PerformanceMeasurePassedInNavigationTiming"/>
@@ -17705,6 +17704,8 @@ Called by update_net_error_codes.py.-->
   <int value="2349" label="V8HTMLElement_Autocapitalize_AttributeGetter"/>
   <int value="2350" label="V8HTMLElement_Autocapitalize_AttributeSetter"/>
   <int value="2351" label="CSSLegacyAlignment"/>
+  <int value="2352" label="SRISignatureCheck"/>
+  <int value="2353" label="SRISignatureSuccess"/>
 </enum>
 
 <enum name="FeedbackSource">