Instrument WebUSB.getDevices/requestDevice for Identifiability study.

Bug: 973801
Change-Id: Ia87925e48d9f0953b5f4e3a2d89472129e4ecee7
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2432424Reviewed-by: Reilly Grant <reillyg@chromium.org>
Commit-Queue: Russ Hamilton <behamilton@google.com>
Cr-Commit-Position: refs/heads/master@{#811456}

third_party/blink/renderer/modules/webusb/usb.cc

@@ -10,6 +10,9 @@
 #include "services/device/public/mojom/usb_device.mojom-blink.h"
 #include "services/device/public/mojom/usb_enumeration_options.mojom-blink.h"
 #include "third_party/blink/public/common/browser_interface_broker_proxy.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/public/mojom/feature_policy/feature_policy.mojom-blink.h"
 #include "third_party/blink/renderer/bindings/core/v8/script_promise.h"
 #include "third_party/blink/renderer/bindings/core/v8/script_promise_resolver.h"
@@ -24,7 +27,9 @@
 #include "third_party/blink/renderer/modules/webusb/usb_device.h"
 #include "third_party/blink/renderer/platform/bindings/exception_state.h"
 #include "third_party/blink/renderer/platform/heap/heap.h"
+#include "third_party/blink/renderer/platform/instrumentation/use_counter.h"
 #include "third_party/blink/renderer/platform/mojo/mojo_helper.h"
+#include "third_party/blink/renderer/platform/privacy_budget/identifiability_digest_helpers.h"
 #include "third_party/blink/renderer/platform/wtf/functional.h"
 
 using device::mojom::blink::UsbDevice;
@@ -187,7 +192,31 @@ void USB::ContextDestroyed() {
   get_permission_requests_.clear();
 }
 
+namespace {
+
+void RecordDevice(LocalFrame* frame, const UsbDeviceInfoPtr& device_info) {
+  IdentifiableSurface s = IdentifiableSurface::FromTypeAndToken(
+      IdentifiableSurface::Type::kWebFeature, WebFeature::kUsbGetDevices);
+  if (!IdentifiabilityStudySettings::Get()->IsSurfaceAllowed(s))
+    return;
+  DCHECK(frame && frame->GetDocument());
+
+  Document* document = frame->GetDocument();
+  IdentifiableTokenBuilder builder;
+  builder.AddToken(device_info->vendor_id);
+  builder.AddToken(device_info->product_id);
+  builder.AddToken(
+      IdentifiabilitySensitiveStringToken(device_info->serial_number));
+
+  IdentifiabilityMetricBuilder(document->UkmSourceID())
+      .Set(s, builder.GetToken())
+      .Record(document->UkmRecorder());
+}
+
+}  // namespace
+
 USBDevice* USB::GetOrCreateDevice(UsbDeviceInfoPtr device_info) {
+  RecordDevice(GetFrame(), device_info);
   USBDevice* device = device_cache_.at(device_info->guid);
   if (!device) {
     String guid = device_info->guid;