[Tab Metrics] Measure FP, FCP and FMP for Foreground Tab during Session Restore

chrome/browser/page_load_metrics/observers/session_restore_foreground_tab_page_load_metrics_observer.h

Index: chrome/browser/page_load_metrics/observers/session_restore_foreground_tab_page_load_metrics_observer.h
diff --git a/chrome/browser/page_load_metrics/observers/session_restore_foreground_tab_page_load_metrics_observer.h b/chrome/browser/page_load_metrics/observers/session_restore_foreground_tab_page_load_metrics_observer.h
new file mode 100644
index 0000000000000000000000000000000000000000..00c31f728a027f4309bbc5febdb60afeee6e7d5d
--- /dev/null
+++ b/chrome/browser/page_load_metrics/observers/session_restore_foreground_tab_page_load_metrics_observer.h
@@ -0,0 +1,59 @@
+// 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 CHROME_BROWSER_PAGE_LOAD_METRICS_OBSERVERS_SESSION_RESTORE_FOREGROUND_TAB_PAGE_LOAD_METRICS_OBSERVER_H_
+#define CHROME_BROWSER_PAGE_LOAD_METRICS_OBSERVERS_SESSION_RESTORE_FOREGROUND_TAB_PAGE_LOAD_METRICS_OBSERVER_H_
+
+#include <memory>
+
+#include "chrome/browser/page_load_metrics/page_load_metrics_observer.h"
+#include "chrome/browser/resource_coordinator/tab_manager.h"
+
+namespace internal {
+
+extern const char kHistogramSessionRestoreForegroundTabFirstPaint[];
+extern const char kHistogramSessionRestoreForegroundTabFirstContentfulPaint[];
+extern const char kHistogramSessionRestoreForegroundTabFirstMeaningfulPaint[];
+
+}  // namespace internal
+
+// Record page load metrics of foreground tabs during session restore

[chrisha, 2017/06/21 15:00:25]

Missing period.

[ducbui, 2017/06/27 19:41:23]

Done.

+class SessionRestoreForegroundTabPageLoadMetricsObserver
+    : public page_load_metrics::PageLoadMetricsObserver {
+ public:
+  SessionRestoreForegroundTabPageLoadMetricsObserver() {}
+
+  static std::unique_ptr<SessionRestoreForegroundTabPageLoadMetricsObserver>
+  CreateIfNeeded();
+
+  ObservePolicy OnStart(content::NavigationHandle* navigation_handle,

[chrisha, 2017/06/21 15:00:25]

These functions are all implementations of the PageLoadMetricsObserver
interface? Then please comment with

// PageLoadMetricsObserver implementation:

[ducbui, 2017/06/27 19:41:23]

Done.

+                        const GURL& currently_committed_url,
+                        bool started_in_foreground) override;
+
+  ObservePolicy OnHidden(
+      const page_load_metrics::mojom::PageLoadTiming& timing,
+      const page_load_metrics::PageLoadExtraInfo& info) override;
+
+  void OnFirstPaintInPage(
+      const page_load_metrics::mojom::PageLoadTiming& timing,
+      const page_load_metrics::PageLoadExtraInfo& extra_info) override;
+
+  void OnFirstContentfulPaintInPage(
+      const page_load_metrics::mojom::PageLoadTiming& timing,
+      const page_load_metrics::PageLoadExtraInfo& extra_info) override;
+
+  void OnFirstMeaningfulPaintInMainFrameDocument(
+      const page_load_metrics::mojom::PageLoadTiming& timing,
+      const page_load_metrics::PageLoadExtraInfo& extra_info) override;
+
+ private:
+  static resource_coordinator::TabManager* GetTabManager();
+
+  static bool HasInitialActiveTabChanged();
+
+  static bool IsInSessionRestore();
+
+  DISALLOW_COPY_AND_ASSIGN(SessionRestoreForegroundTabPageLoadMetricsObserver);
+};
+#endif  // CHROME_BROWSER_PAGE_LOAD_METRICS_OBSERVERS_SESSION_RESTORE_FOREGROUND_TAB_PAGE_LOAD_METRICS_OBSERVER_H_