Add Foreground-to-FirstMeaningfulPaint histogram

chrome/browser/page_load_metrics/page_load_metrics_util.h

 // Copyright 2015 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_PAGE_LOAD_METRICS_UTIL_H_
 #define CHROME_BROWSER_PAGE_LOAD_METRICS_PAGE_LOAD_METRICS_UTIL_H_
 
 #include "base/metrics/histogram_macros.h"
 #include "base/optional.h"
 #include "base/time/time.h"
@@ skipping 87 matching lines @@
 // When a page is backgrounded, some events (e.g. paint) are delayed. Since
 // these data points can skew the mean, they should not be mixed with timing
 // events that occurred in the foreground.
 // If the event time delta and background time delta are equal, we still
 // consider the event to be logged in the foreground histogram since any
 // background specific handling would not yet have been applied to that event.
 bool WasStartedInForegroundOptionalEventInForeground(
     const base::Optional<base::TimeDelta>& event,
     const PageLoadExtraInfo& info);
 
+// Returns true if:
+// - We have timing information for the event.
+// - The page load started in the background.
+// - Moved to the foreground prior to the event.
+// - Not moved back to the background prior to the event.
+bool WasStartedInBackgroundOptionalEventInForeground(
+    const base::Optional<base::TimeDelta>& event,
+    const PageLoadExtraInfo& info);
+
 PageAbortInfo GetPageAbortInfo(const PageLoadExtraInfo& info);
 
 // Get the duration of time that the page spent in the foreground, from
 // navigation start until one of the following events:
 // * the load of the main resource fails
 // * the page load is stopped
 // * the tab hosting the page is closed
 // * the render process hosting the page goes away
 // * a new navigation which later commits is initiated in the same tab
 // * the tab hosting the page is backgrounded
 base::Optional<base::TimeDelta> GetInitialForegroundDuration(
     const PageLoadExtraInfo& info,
     base::TimeTicks app_background_time);
 
 // Whether the given loading behavior was observed in any frame (either the main
 // frame or a subframe).
 bool DidObserveLoadingBehaviorInAnyFrame(
     const page_load_metrics::PageLoadExtraInfo& info,
     blink::WebLoadingBehaviorFlag behavior);
 
 }  // namespace page_load_metrics
 
 #endif  // CHROME_BROWSER_PAGE_LOAD_METRICS_PAGE_LOAD_METRICS_UTIL_H_