Index: tools/metrics/histograms/histograms.xml |
diff --git a/tools/metrics/histograms/histograms.xml b/tools/metrics/histograms/histograms.xml |
index 7018035bfe891e9a33e4124264a1c0f14ba56b88..d988f00e64654bff7dd840124b5bc164ead98444 100644 |
--- a/tools/metrics/histograms/histograms.xml |
+++ b/tools/metrics/histograms/histograms.xml |
@@ -10081,6 +10081,17 @@ other types of suffix sets. |
</summary> |
</histogram> |
+<histogram name="NewTabPage.ThumbnailFallbackRate" units="%"> |
+ <summary> |
+ The percentage of times most visited tiles use the fallback thumbnail. Only |
+ requests that actually specify a fallback thumbnail are considered here. We |
+ measure the rate instead of the number of errors because multiple attempts |
+ are made to load thumbnails at different times during the NTP's lifetime. |
+ Each NTP session's error rate is logged after the user navigates to a new |
+ URL from that NTP. |
+ </summary> |
+</histogram> |
+ |
<histogram name="NewTabPage.VisibleScreenshots"> |
<summary> |
The number of screenshots that were cached for the visible suggestions on |