Make OnDataTimedout and OnDidPerformInstallableCheck mutually exclusive.

chrome/browser/android/webapps/add_to_homescreen_data_fetcher.cc

Index: chrome/browser/android/webapps/add_to_homescreen_data_fetcher.cc
diff --git a/chrome/browser/android/webapps/add_to_homescreen_data_fetcher.cc b/chrome/browser/android/webapps/add_to_homescreen_data_fetcher.cc
index 2dea7aa3a00b0457d742b1b3fc685e6c50b030e1..308503f90974d730d905dd4c063cc4cdcd4acce7 100644
--- a/chrome/browser/android/webapps/add_to_homescreen_data_fetcher.cc
+++ b/chrome/browser/android/webapps/add_to_homescreen_data_fetcher.cc
@@ -212,6 +212,9 @@ void AddToHomescreenDataFetcher::OnDidPerformInstallableCheck(
   if (!web_contents() || !weak_observer_)
     return;
 
+  if (is_installable_check_complete_)

[dominickn, 2017/02/28 23:17:12]

Combine the two conditionals:

if (!web_contents() || !weak_observer_ || is_installable_check_complete_)
  return;

[F, 2017/02/28 23:22:06]

Done.

+    return;
+
   is_installable_check_complete_ = true;
 
   bool webapk_compatible = false;