Use base::Clock instead of base::Time::Now in AppSearchProvider.

chrome/browser/ui/app_list/search/app_result.cc

Index: chrome/browser/ui/app_list/search/app_result.cc
diff --git a/chrome/browser/ui/app_list/search/app_result.cc b/chrome/browser/ui/app_list/search/app_result.cc
index ae0166af362a79a9508a78b45ed708fff8f20dc5..74c7055d53f082afee7daae1debbb8f38e9eb0c1 100644
--- a/chrome/browser/ui/app_list/search/app_result.cc
+++ b/chrome/browser/ui/app_list/search/app_result.cc
@@ -81,7 +81,11 @@ void AppResult::UpdateFromMatch(const TokenizedString& title,
 void AppResult::UpdateFromLastLaunched(const base::Time& current_time,
                                        const base::Time& last_launched) {
   base::TimeDelta delta = current_time - last_launched;
-  DCHECK_LE(0, delta.InSeconds());
+  if (current_time < last_launched) {

[Matt Giuca, 2014/12/10 07:16:12]

This certainly needs an explanation. (From the bug, I understand that this is a
"basically can never happen except on full moon" scenario, so you should vaguely
explain it and say why you do 1.0.)

[calamity, 2014/12/11 05:05:01]

Done.

+    set_relevance(1.0);
+    return;
+  }
+
   const int kSecondsInWeek = 60 * 60 * 24 * 7;
 
   // Set the relevance to a value between 0 and 1. This function decays as the