Added UMA for usage of BudgetAPI calls.

chrome/browser/budget_service/budget_manager.h

Index: chrome/browser/budget_service/budget_manager.h
diff --git a/chrome/browser/budget_service/budget_manager.h b/chrome/browser/budget_service/budget_manager.h
index 99fa4fe2c9dea724a01c58b8980df6b1d63c3036..a9e18179bd967a0d57e992263f53d435261cfd54 100644
--- a/chrome/browser/budget_service/budget_manager.h
+++ b/chrome/browser/budget_service/budget_manager.h
@@ -63,6 +63,12 @@ class BudgetManager : public KeyedService {
  private:
   friend class BudgetManagerTest;
 
+  // Called as a callback from BudgetDatabase when it returns the GetBudget
+  // details.

[Peter Beverloo, 2016/11/28 10:59:00]

micro nit: I don't think these comments (dito re: the following two methods) add
any value at all. Up to you.

[harkness, 2016/11/28 13:58:04]

I agree in this case. I've removed this one and the other two.

+  void DidGetBudget(const GetBudgetCallback& callback,
+                    blink::mojom::BudgetServiceErrorType error,
+                    mojo::Array<blink::mojom::BudgetStatePtr> budget);
+
   // Called as a callback from BudgetDatabase after it made a SpendBudget
   // decision.
   void DidConsume(const ConsumeCallback& callback,