customtabs: Properly report time from intent to first commit.

tools/metrics/histograms/histograms.xml

Index: tools/metrics/histograms/histograms.xml
diff --git a/tools/metrics/histograms/histograms.xml b/tools/metrics/histograms/histograms.xml
index 9219acd94b8852b04e91a09afe67e02ebef73400..97e9d8b63cd9b75af62c9b11fa79d15f61ce7da7 100644
--- a/tools/metrics/histograms/histograms.xml
+++ b/tools/metrics/histograms/histograms.xml
@@ -9328,6 +9328,14 @@ http://cs/file:chrome/histograms.xml - but prefer this file for new entries.
   <owner>lizeb@chromium.org</owner>
   <summary>
     Time between the intent arrival to a Custom Tab and the first navigation
+    start, if the navigation is successful. Non-&quot;Herb&quot; mode.
+  </summary>
+</histogram>
+
+<histogram name="CustomTabs.IntentToFirstCommitNavigationTime3" units="ms">
+  <owner>lizeb@chromium.org</owner>
+  <summary>
+    Time between the intent arrival to a Custom Tab and the first navigation
     commit, if the navigation is successful. Similar in principle to
     Startup.FirstCommitNavigationTime. Non-&quot;Herb&quot; mode.
   </summary>
@@ -117628,6 +117636,7 @@ from previous Chrome versions.
   <affected-histogram
       name="ChromeGeneratedCustomTab.IntentToFirstCommitNavigationTime2"/>
   <affected-histogram name="CustomTabs.IntentToFirstCommitNavigationTime2"/>

[Ilya Sherman, 2017/03/28 18:14:26]

Would it be appropriate to stop recording the previous version of this metric?

[Benoit L, 2017/03/31 16:10:23]

It is still valuable, with the updated documentation.

+  <affected-histogram name="CustomTabs.IntentToFirstCommitNavigationTime3"/>
   <affected-histogram name="Startup.FirstCommitNavigationTime2"/>
 </histogram_suffixes>