[Offline Pages] Feature flag to allow concurrent background loading on svelte

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 7a58ada284ba83ed9c9023d4329ff9547be7b23b..766c4420ee570a13e34ac4dcbcf804a8af2cb367 100644
--- a/tools/metrics/histograms/histograms.xml
+++ b/tools/metrics/histograms/histograms.xml
@@ -90323,6 +90323,7 @@ value.
   <int value="-661978438" label="enable-data-reduction-proxy-lo-fi"/>
   <int value="-660160292" label="enable-apps-show-on-first-paint"/>
   <int value="-650504533" label="enable-speculative-launch-service-worker"/>
+  <int value="-650176557" label="OfflinePagesSvelteConcurrentLoading:enabled"/>
   <int value="-649956990" label="enable-harfbuzz-rendertext"/>
   <int value="-645455405" label="MacViewsNativeDialogs:enabled"/>
   <int value="-641719457" label="disable-compositor-touch-hit-testing"/>
@@ -90464,6 +90465,7 @@ value.
   <int value="56723110" label="enable-webfonts-intervention"/>
   <int value="59784035" label="ImeThread:disabled"/>
   <int value="61205887" label="enable-text-input-focus-manager"/>
+  <int value="64942701" label="OfflinePagesSvelteConcurrentLoading:disabled"/>
   <int value="70878462" label="WebAssembly:disabled"/>
   <int value="75747474" label="disable-webview-signin-flow"/>
   <int value="78998551" label="disable-hosted-app-shim-creation"/>