Do not show the lite chip during a pending navigation

See bug for more context.

Bug: 903895
Change-Id: I86c029059a2896084f36af46df56a70a91620838
Reviewed-on: https://chromium-review.googlesource.com/c/1330202Reviewed-by: Doug Arnett <dougarnett@chromium.org>
Commit-Queue: Robert Ogden <robertogden@chromium.org>
Cr-Commit-Position: refs/heads/master@{#607295}

chrome/browser/previews/android/previews_android_bridge.cc

@@ -36,6 +36,11 @@ jboolean PreviewsAndroidBridge::ShouldShowPreviewUI(
   if (!web_contents)
     return false;
 
+  // Do not show the lite page chip between navigation start and navigation
+  // finish.
+  if (web_contents->GetController().GetPendingEntry())
+    return false;
+
   PreviewsUITabHelper* tab_helper =
       PreviewsUITabHelper::FromWebContents(web_contents);
   if (!tab_helper)