Emit UMAs for metrics from memory instrumentation service.

chrome/browser/metrics/process_memory_metrics_emitter_browsertest.cc

+// 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.
+
+#include "chrome/browser/metrics/process_memory_metrics_emitter.h"
+
+#include "base/message_loop/message_loop.h"
+#include "chrome/test/base/in_process_browser_test.h"
+#include "content/public/test/test_utils.h"
+
+namespace {
+
+class ProcessMemoryMetricsEmitterFake : public ProcessMemoryMetricsEmitter {
+ public:
+  ProcessMemoryMetricsEmitterFake() {}
+
+ private:
+  ~ProcessMemoryMetricsEmitterFake() override {}
+
+  void ReceivedMemoryDump(
+      uint64_t dump_guid,
+      bool success,
+      memory_instrumentation::mojom::GlobalMemoryDumpPtr ptr) override {
+    EXPECT_TRUE(success);
+    base::MessageLoop::current()->QuitWhenIdle();
+  }
+
+  DISALLOW_COPY_AND_ASSIGN(ProcessMemoryMetricsEmitterFake);
+};
+
+}  // namespace
+
+class ProcessMemoryMetricsEmitterTest : public InProcessBrowserTest {
+ public:
+  ProcessMemoryMetricsEmitterTest() {}
+  ~ProcessMemoryMetricsEmitterTest() override {}
+
+ private:
+  DISALLOW_COPY_AND_ASSIGN(ProcessMemoryMetricsEmitterTest);
+};
+
+IN_PROC_BROWSER_TEST_F(ProcessMemoryMetricsEmitterTest, FetchAndEmitMetrics) {
+  // Intentionally let emitter leave scope to check that it correctly keeps
+  // itself alive.
+  {
+    scoped_refptr<ProcessMemoryMetricsEmitterFake> emitter(
+        new ProcessMemoryMetricsEmitterFake);
+    emitter->FetchAndEmitProcessMemoryMetrics();
+  }
+
+  content::RunMessageLoop();
+}