[Start] Fix new tab button shown delay.

(cherry picked from commit 5e0d01d)

Bug: 1354865
Change-Id: I98bdbff40722a9ddbeac92f23f55007f53545a2f
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/3843348
Reviewed-by: Xi Han <hanxi@chromium.org>
Commit-Queue: Hao Dong <spdonghao@chromium.org>
Cr-Original-Commit-Position: refs/heads/main@{#1037763}
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/3851021
Cr-Commit-Position: refs/branch-heads/5249@{#43}
Cr-Branched-From: 4f7bea5-refs/heads/main@{#1036826}

chrome/browser/ui/android/toolbar/java/src/org/chromium/chrome/browser/toolbar/top/StartSurfaceToolbarMediator.java

@@ -222,8 +222,10 @@ private boolean isOnATab() {
 
     /** Returns whether it's on grid tab switcher surface. */
     private boolean isOnGridTabSwitcher() {
-        return mIsRefactorEnabled ? mLayoutType == LayoutType.TAB_SWITCHER
-                                  : mStartSurfaceState == StartSurfaceState.SHOWN_TABSWITCHER;
+        return mIsRefactorEnabled
+                ? mLayoutType == LayoutType.TAB_SWITCHER
+                : (mStartSurfaceState == StartSurfaceState.SHOWN_TABSWITCHER
+                        || mStartSurfaceState == StartSurfaceState.SHOWING_TABSWITCHER);
     }
 
     /**