Remove startup metrics recorded 7 minutes after system start.

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 a2ebc339f3f0de9f64c5c8b696e10feac07b72fa..853b8e4b18b5536ada5c67d723782aa827f837a3 100644
--- a/tools/metrics/histograms/histograms.xml
+++ b/tools/metrics/histograms/histograms.xml
@@ -63174,6 +63174,9 @@ http://cs/file:chrome/histograms.xml - but prefer this file for new entries.
 </histogram>
 
 <histogram name="Startup.BrowserMessageLoopStartTimeFromMainEntry" units="ms">
+  <obsolete>
+    Deprecated 12/2016. crbug.com/634408
+  </obsolete>
   <owner>fdoray@chromium.org</owner>
   <owner>gab@chromium.org</owner>
   <summary>
@@ -63181,12 +63184,15 @@ http://cs/file:chrome/histograms.xml - but prefer this file for new entries.
     stat is only recorded after 7 minutes of OS uptime to try to mitigate the
     variance resulting from Chrome being autostarted. Replaced with
     Startup.BrowserMessageLoopStartTimeFromMainEntry2 which is recorded all the
-    time. TODO(fdoray): Deprecate this once M54 hits stable. crbug.com/634408
+    time.
   </summary>
 </histogram>
 
 <histogram name="Startup.BrowserMessageLoopStartTimeFromMainEntry.FirstRun"
     units="ms">
+  <obsolete>
+    Deprecated 12/2016. crbug.com/634408
+  </obsolete>
   <owner>fdoray@chromium.org</owner>
   <owner>gab@chromium.org</owner>
   <summary>
@@ -63194,8 +63200,7 @@ http://cs/file:chrome/histograms.xml - but prefer this file for new entries.
     run. This stat is only recorded after 7 minutes of OS uptime to try to
     mitigate the variance resulting from Chrome being autostarted. Replaced with
     Startup.BrowserMessageLoopStartTimeFromMainEntry.FirstRun2 which is recorded
-    all the time. TODO(fdoray): Deprecate this once M54 hits stable.
-    crbug.com/634408
+    all the time.
   </summary>
 </histogram>
 
@@ -63516,6 +63521,9 @@ http://cs/file:chrome/histograms.xml - but prefer this file for new entries.
 </histogram>
 
 <histogram name="Startup.LoadTime.ExeMainToDllMain">
+  <obsolete>
+    Deprecated 12/2016. crbug.com/634408
+  </obsolete>
   <owner>fdoray@chromium.org</owner>
   <owner>gab@chromium.org</owner>
   <summary>
@@ -63523,7 +63531,6 @@ http://cs/file:chrome/histograms.xml - but prefer this file for new entries.
     stat is only recorded after 7 minutes of OS uptime to try to mitigate the
     variance resulting from Chrome being autostarted. Replaced with
     Startup.LoadTime.ExeMainToDllMain2 which is recorded all the time.
-    TODO(fdoray): Deprecate this once M54 hits stable. crbug.com/634408
   </summary>
 </histogram>
 
@@ -63536,6 +63543,9 @@ http://cs/file:chrome/histograms.xml - but prefer this file for new entries.
 </histogram>
 
 <histogram name="Startup.LoadTime.ProcessCreateToDllMain">
+  <obsolete>
+    Deprecated 12/2016. crbug.com/634408
+  </obsolete>
   <owner>fdoray@chromium.org</owner>
   <owner>gab@chromium.org</owner>
   <summary>
@@ -63543,7 +63553,6 @@ http://cs/file:chrome/histograms.xml - but prefer this file for new entries.
     recorded after 7 minutes of OS uptime to try to mitigate the variance
     resulting from Chrome being autostarted. Replaced with
     Startup.LoadTime.ProcessCreateToDllMain2 which is recorded all the time.
-    TODO(fdoray): Deprecate this once M54 hits stable. crbug.com/634408
   </summary>
 </histogram>
 
@@ -63554,6 +63563,9 @@ http://cs/file:chrome/histograms.xml - but prefer this file for new entries.
 </histogram>
 
 <histogram name="Startup.LoadTime.ProcessCreateToExeMain">
+  <obsolete>
+    Deprecated 12/2016. crbug.com/634408
+  </obsolete>
   <owner>fdoray@chromium.org</owner>
   <owner>gab@chromium.org</owner>
   <summary>
@@ -63561,7 +63573,7 @@ http://cs/file:chrome/histograms.xml - but prefer this file for new entries.
     chrome.exe. This stat is only recorded after 7 minutes of OS uptime to try
     to mitigate the variance resulting from Chrome being autostarted. Replaced
     with Startup.LoadTime.ProcessCreateToExeMain2 which is recorded all the
-    time. TODO(fdoray): Deprecate this once M54 hits stable. crbug.com/634408
+    time.
   </summary>
 </histogram>