[IntentHandling] Fix common apps navigation throttle error.

This CL fixes an error in common apps navigation throttle. After load
app icons, we should return true to indicate we need to defer the
navigation. Otherwise it will cause DCHECK error when resume navigation.

BUG=853604

Change-Id: Ic618686070ab7eb237adf7b194de61cdceafcfd4
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2155764Reviewed-by: Dominick Ng <dominickn@chromium.org>
Commit-Queue: Maggie Cai <mxcai@chromium.org>
Cr-Commit-Position: refs/heads/master@{#760404}

chrome/browser/chromeos/apps/intent_helper/common_apps_navigation_throttle.cc

@@ -239,7 +239,7 @@ bool CommonAppsNavigationThrottle::ShouldDeferNavigation(
       base::BindOnce(
           &CommonAppsNavigationThrottle::OnDeferredNavigationProcessed,
           weak_factory_.GetWeakPtr()));
-  return false;
+  return true;
 }
 
 void CommonAppsNavigationThrottle::OnDeferredNavigationProcessed(