[WIP] off-main-thread loading

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 286baa8419050d1975c30406e34505c8758eddc1..8d2d19f249ba4477f9b3e48c47599e4acd0ee9ab 100644
--- a/tools/metrics/histograms/histograms.xml
+++ b/tools/metrics/histograms/histograms.xml
@@ -101236,6 +101236,7 @@ from previous Chrome versions.
   <int value="223662457" label="BackgroundLoadingForDownloads:enabled"/>
   <int value="243557364" label="ash-force-enable-palette"/>
   <int value="244697230" label="enable-theme-color-in-tabbed-mode"/>
+  <int value="259021228" label="OffMainThreadFetch:disabled"/>
   <int value="262382944" label="GuestViewCrossProcessFrames:disabled"/>
   <int value="266702296" label="disable-plugin-power-saver"/>
   <int value="270267831" label="enable-scripts-require-action"/>
@@ -101670,6 +101671,7 @@ from previous Chrome versions.
   <int value="1951466218" label="enable-data-reduction-proxy-lite-page"/>
   <int value="1955677113" label="trace-export-events-to-etw"/>
   <int value="1958387645" label="ScanCardsInWebPayments:enabled"/>
+  <int value="1959148757" label="OffMainThreadFetch:enabled"/>
   <int value="1960169775" label="NewPhotoPicker:disabled"/>
   <int value="1961425320" label="force-qtkit"/>
   <int value="1964816410" label="AndroidPayIntegrationV2:enabled"/>