Gate direct fingerprinting surface UKM digest on study participation.

We want to abort the instrumentation as early as possible for users
not in the study, so each overload has its own guard clause.

Bug: 973801
Change-Id: Ifed7e75ef90cff0bc41cad2eeaaeaf5bea340e56
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2341809
Commit-Queue: Dylan Cutler <dylancutler@google.com>
Reviewed-by: Asanka Herath <asanka@chromium.org>
Reviewed-by: Nate Chapin <japhet@chromium.org>
Cr-Commit-Position: refs/heads/master@{#796282}

third_party/blink/renderer/core/frame/dactyloscoper.cc

@@ -5,6 +5,7 @@
 #include "third_party/blink/renderer/core/frame/dactyloscoper.h"
 
 #include "third_party/blink/public/common/privacy_budget/identifiability_metric_builder.h"
+#include "third_party/blink/public/common/privacy_budget/identifiability_study_settings.h"
 #include "third_party/blink/public/common/privacy_budget/identifiable_token_builder.h"
 #include "third_party/blink/renderer/core/dom/document.h"
 #include "third_party/blink/renderer/core/frame/local_dom_window.h"
@@ -36,6 +37,8 @@ void Dactyloscoper::Record(ExecutionContext* context, WebFeature feature) {
 void Dactyloscoper::RecordDirectSurface(ExecutionContext* context,
                                         WebFeature feature,
                                         IdentifiableToken value) {
+  if (!IdentifiabilityStudySettings::Get()->IsActive())
+    return;
   auto* window = DynamicTo<LocalDOMWindow>(context);
   if (!window)
     return;
@@ -48,6 +51,8 @@ void Dactyloscoper::RecordDirectSurface(ExecutionContext* context,
 void Dactyloscoper::RecordDirectSurface(ExecutionContext* context,
                                         WebFeature feature,
                                         String str) {
+  if (!IdentifiabilityStudySettings::Get()->IsActive())
+    return;
   if (str.IsEmpty())
     return;
   Dactyloscoper::RecordDirectSurface(context, feature,
@@ -57,6 +62,8 @@ void Dactyloscoper::RecordDirectSurface(ExecutionContext* context,
 void Dactyloscoper::RecordDirectSurface(ExecutionContext* context,
                                         WebFeature feature,
                                         Vector<String> strs) {
+  if (!IdentifiabilityStudySettings::Get()->IsActive())
+    return;
   if (strs.IsEmpty())
     return;
   IdentifiableTokenBuilder builder;