Add UKM metrics for FileSystemAPI web requests.

kRequestedFileSystemTemporary is recently removed from UseCounters in
crrev.com/c/2414917 along with a number of other highly used metrics.
This metric and kRequestedFileSystemPersistent are now replaced with
dedicated UKMs.

Bug: 990731, 1129061
Change-Id: Iba8be6a1fe4063388843f2a54f95827fefd3a42f
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2421746Reviewed-by: Alexei Svitkine <asvitkine@chromium.org>
Reviewed-by: Marijn Kruisselbrink <mek@chromium.org>
Commit-Queue: Ramin Halavati <rhalavati@chromium.org>
Cr-Commit-Position: refs/heads/master@{#812579}

components/page_load_metrics/browser/observers/use_counter/ukm_features.cc

@@ -121,7 +121,6 @@ UseCounterPageLoadMetricsObserver::GetAllowedUkmFeatures() {
           WebFeature::kLazyLoadFrameLoadingAttributeEager,
           WebFeature::kLazyLoadImageLoadingAttributeLazy,
           WebFeature::kLazyLoadImageLoadingAttributeEager,
-          WebFeature::kRequestedFileSystemPersistent,
           WebFeature::kWebOTP,
           WebFeature::kBaseWithCrossOriginHref,
           WebFeature::kWakeLockAcquireScreenLock,

third_party/blink/renderer/modules/filesystem/BUILD.gn

@@ -66,6 +66,7 @@ blink_modules_sources("filesystem") {
 
   deps = [
     "//components/services/filesystem/public/mojom:mojom_blink",
+    "//services/metrics/public/cpp:ukm_builders",
     "//third_party/blink/renderer/platform",
   ]
 }

third_party/blink/renderer/modules/filesystem/DEPS

 include_rules = [
     "+base/files/file.h",
+    "+services/metrics/public/cpp",
     "-third_party/blink/renderer/modules",
     "+third_party/blink/renderer/modules/event_target_modules.h",
     "+third_party/blink/renderer/modules/filesystem",

third_party/blink/renderer/modules/filesystem/dom_window_file_system.cc

@@ -25,6 +25,9 @@
 
 #include "third_party/blink/renderer/modules/filesystem/dom_window_file_system.h"
 
+#include "services/metrics/public/cpp/mojo_ukm_recorder.h"
+#include "services/metrics/public/cpp/ukm_builders.h"
+#include "services/metrics/public/cpp/ukm_source_id.h"
 #include "third_party/blink/public/mojom/filesystem/file_system.mojom-blink.h"
 #include "third_party/blink/renderer/core/dom/dom_exception.h"
 #include "third_party/blink/renderer/core/fileapi/file_error.h"
@@ -74,10 +77,19 @@ void DOMWindowFileSystem::webkitRequestFileSystem(
     return;
   }
 
+  auto* ukm_recorder = window.document()->UkmRecorder();
+  const ukm::SourceId source_id = window.document()->UkmSourceID();
+
   if (file_system_type == mojom::blink::FileSystemType::kTemporary) {
     UseCounter::Count(window, WebFeature::kRequestedFileSystemTemporary);
+    ukm::builders::FileSystemAPI_WebRequest(source_id)
+        .SetTemporary(true)
+        .Record(ukm_recorder->Get());
   } else if (file_system_type == mojom::blink::FileSystemType::kPersistent) {
     UseCounter::Count(window, WebFeature::kRequestedFileSystemPersistent);
+    ukm::builders::FileSystemAPI_WebRequest(source_id)
+        .SetPersistent(true)
+        .Record(ukm_recorder->Get());
   }
 
   auto success_callback_wrapper =

tools/metrics/ukm/ukm.xml

@@ -4047,6 +4047,24 @@ be describing additional metrics about the same event.
   </metric>
 </event>
 
+<event name="FileSystemAPI.WebRequest">
+  <owner>mek@chromium.org</owner>
+  <owner>rhalavatigit@chromium.org</owner>
+  <summary>
+    Logged when a website requests accessing FileSystem API.
+  </summary>
+  <metric name="Persistent">
+    <summary>
+      Marks a request for a Persistent FileSystem.
+    </summary>
+  </metric>
+  <metric name="Temporary">
+    <summary>
+      Marks a request for a Temporary FileSystem.
+    </summary>
+  </metric>
+</event>
+
 <event name="FontMatchAttempts">
   <owner>caraitto@chromium.org</owner>
   <owner>pauljensen@chromium.org</owner>