Turn off desktop IPH in incognito for privacy concern

Temporarily turn off IPH in incognito as a concern was raised that
the IPH backend ignores incognito and writes to the parent profile.

See https://bugs.chromium.org/p/chromium/issues/detail?id=1128728#c30

Change-Id: Ide0f21b3cdacd50f7d1ce7462d203139b0bfba31
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2431731
Auto-Submit: Keren Zhu <kerenzhu@chromium.org>
Commit-Queue: Collin Baker <collinbaker@chromium.org>
Reviewed-by: Collin Baker <collinbaker@chromium.org>
Cr-Commit-Position: refs/heads/master@{#810789}

chrome/browser/ui/views/in_product_help/feature_promo_controller_views.cc

@@ -47,6 +47,12 @@ bool FeaturePromoControllerViews::MaybeShowPromoWithParams(
   if (promos_blocked_for_testing_)
     return false;
 
+  // Temporarily turn off IPH in incognito as a concern was raised that
+  // the IPH backend ignores incognito and writes to the parent profile.
+  // See https://bugs.chromium.org/p/chromium/issues/detail?id=1128728#c30
+  if (browser_view_->GetProfile()->IsIncognitoProfile())
+    return false;
+
   if (snooze_service_->IsBlocked(iph_feature))
     return false;