Refactor UKM interface for mojo-ification

components/ukm/public/ukm_recorder.h

Index: components/ukm/public/ukm_recorder.h
diff --git a/components/ukm/public/ukm_recorder.h b/components/ukm/public/ukm_recorder.h
new file mode 100644
index 0000000000000000000000000000000000000000..e301a9dd251add6199f97347e45675d9ccd24e41
--- /dev/null
+++ b/components/ukm/public/ukm_recorder.h
@@ -0,0 +1,97 @@
+// Copyright 2017 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#ifndef COMPONENTS_UKM_PUBLIC_UKM_RECORDER_H_
+#define COMPONENTS_UKM_PUBLIC_UKM_RECORDER_H_
+
+#include <stddef.h>
+
+#include "base/callback.h"
+#include "base/feature_list.h"
+#include "base/macros.h"
+#include "base/threading/thread_checker.h"
+#include "components/ukm/public/interfaces/ukm_interface.mojom.h"
+#include "components/ukm/public/ukm_entry_builder.h"
+#include "url/gurl.h"
+
+class PluginInfoMessageFilter;
+class UkmPageLoadMetricsObserver;
+
+namespace autofill {
+class AutofillMetrics;
+}
+
+namespace content {
+class RenderFrameImpl;
+}
+
+namespace translate {
+class TranslateRankerImpl;
+}
+
+namespace payments {
+class JourneyLogger;
+}
+
+namespace ukm {
+
+class UkmEntryBuilder;
+class UkmInterface;
+class TestRecordingHelper;
+
+// This feature controls whether UkmService should be created.
+extern const base::Feature kUkmFeature;
+
+typedef int64_t SourceId;
+
+// Interface for recording UKM
+class UkmRecorder {
+ public:
+  UkmRecorder();
+  virtual ~UkmRecorder();
+
+  // Get the new source ID, which is unique for the duration of a browser
+  // session.
+  static SourceId GetNewSourceID();
+
+  // Update the URL on the source keyed to the given source ID. If the source
+  // does not exist, it will create a new UkmSource object.
+  virtual void UpdateSourceURL(SourceId source_id, const GURL& url) = 0;
+
+ private:
+  friend autofill::AutofillMetrics;
+  friend payments::JourneyLogger;
+  friend PluginInfoMessageFilter;
+  friend UkmPageLoadMetricsObserver;
+  friend translate::TranslateRankerImpl;
+  friend TestRecordingHelper;
+  friend UkmInterface;
+  friend content::RenderFrameImpl;
+  FRIEND_TEST_ALL_PREFIXES(UkmServiceTest, AddEntryWithEmptyMetrics);
+  FRIEND_TEST_ALL_PREFIXES(UkmServiceTest, EntryBuilderAndSerialization);
+  FRIEND_TEST_ALL_PREFIXES(UkmServiceTest,
+                           LogsUploadedOnlyWhenHavingSourcesOrEntries);
+  FRIEND_TEST_ALL_PREFIXES(UkmServiceTest, MetricsProviderTest);
+  FRIEND_TEST_ALL_PREFIXES(UkmServiceTest, PersistAndPurge);
+  FRIEND_TEST_ALL_PREFIXES(UkmServiceTest, WhitelistEntryTest);
+
+  // Get a new UkmEntryBuilder object for the specified source ID and event,
+  // which can get metrics added to.
+  //
+  // This API being private is intentional. Any client using UKM needs to
+  // declare itself to be a friend of UkmService and go through code review
+  // process.
+  std::unique_ptr<UkmEntryBuilder> GetEntryBuilder(SourceId source_id,
+                                                   const char* event_name);
+
+ private:
+  // Add an entry to the UkmEntry list.
+  virtual void AddEntry(mojom::UkmEntryPtr entry) = 0;
+
+  DISALLOW_COPY_AND_ASSIGN(UkmRecorder);
+};
+
+}  // namespace ukm
+
+#endif  // COMPONENTS_UKM_PUBLIC_UKM_RECORDER_H_