Added UMA stats to track the budget for any service worker which receives a

chrome/browser/push_messaging/background_budget_service.h

Index: chrome/browser/push_messaging/background_budget_service.h
diff --git a/chrome/browser/push_messaging/background_budget_service.h b/chrome/browser/push_messaging/background_budget_service.h
index 717545a02a6ac464045d7268f625bd42b39610d2..e5e5674ef6fe1c8a6f41e69183e054980450e222 100644
--- a/chrome/browser/push_messaging/background_budget_service.h
+++ b/chrome/browser/push_messaging/background_budget_service.h
@@ -33,6 +33,14 @@ class BackgroundBudgetService : public KeyedService {
 
   static void RegisterProfilePrefs(user_prefs::PrefRegistrySyncable* registry);
 
+  enum class CostType {
+    // The cost of silencing a push message.
+    SILENT_PUSH = 0,
+  };
+
+  // Query for the base cost for any background processing.
+  static double GetCost(CostType type);
+
   // Get the budget associated with the origin. This is returned as the double
   // budget. Budget will be a value between 0.0 and
   // SiteEngagementScore::kMaxPoints.
@@ -51,6 +59,9 @@ class BackgroundBudgetService : public KeyedService {
   // The clock used to vend times.
   std::unique_ptr<base::Clock> clock_;
 
+  // Array holding the costs for various background operations.
+  static double costs_[];

[Peter Beverloo, 2016/05/17 15:54:28]

nit: remove

[harkness, 2016/05/17 16:18:05]

Done.

+
   Profile* profile_;
   DISALLOW_COPY_AND_ASSIGN(BackgroundBudgetService);
 };