Connect Mojo budget_service to BudgetManager implementation of Reserve.

chrome/browser/budget_service/budget_database.h

Index: chrome/browser/budget_service/budget_database.h
diff --git a/chrome/browser/budget_service/budget_database.h b/chrome/browser/budget_service/budget_database.h
index b2017aad82c96302f4d113eae5d36bbf9a1120cf..32f2a9104b07ce0bc07fa4474b5b36a17383a2d7 100644
--- a/chrome/browser/budget_service/budget_database.h
+++ b/chrome/browser/budget_service/budget_database.h
@@ -32,12 +32,15 @@ class Profile;
 // assigned to an origin. The class uses an underlying LevelDB.
 class BudgetDatabase {
  public:
-  // Callback for setting a budget value.
-  using StoreBudgetCallback = base::Callback<void(bool success)>;
-
   // Callback for getting a list of all budget chunks.
   using GetBudgetCallback = blink::mojom::BudgetService::GetBudgetCallback;
 
+  // Callback for SpendBudget. This will be invoked only after the spend has
+  // been written to the database. It takes two values, an error type which
+  // indicates if there was a particular error, and a bool that indicates
+  // whether the origin had budget to spend.
+  using SpendBudgetCallback = blink::mojom::BudgetService::ReserveCallback;

[Peter Beverloo, 2016/09/08 17:16:06]

We should probably just redefine the callback format. A reader interested in
spending budget now suddenly has to look up what reserving budget means (but I
want to spend it!), which lives in a generated file.

That'd also save you from having to explain the arguments in English, as you do
above.

[harkness, 2016/09/13 13:41:28]

Done.

+
   // The database_dir specifies the location of the budget information on
   // disk. The task_runner is used by the ProtoDatabase to handle all blocking
   // calls and disk access.
@@ -50,13 +53,11 @@ class BudgetDatabase {
   // sequence of time points and the expected budget at those times.
   void GetBudgetDetails(const GURL& origin, const GetBudgetCallback& callback);
 
-  // Spend a particular amount of budget for an origin. The callback takes
-  // a boolean which indicates whether the origin had enough budget to spend.
-  // If it returns success, then the budget was deducted and the result written
-  // to the database.
+  // Spend a particular amount of budget for an origin. The callback indicates
+  // whether there was an error and if the origin had enough budget.
   void SpendBudget(const GURL& origin,
                    double amount,
-                   const StoreBudgetCallback& callback);
+                   const SpendBudgetCallback& callback);
 
  private:
   friend class BudgetDatabaseTest;
@@ -93,8 +94,10 @@ class BudgetDatabase {
     DISALLOW_COPY_AND_ASSIGN(BudgetInfo);
   };
 
-  using AddToCacheCallback = base::Callback<void(bool success)>;
-  using SyncCacheCallback = base::Callback<void(bool success)>;
+  // Callback for writing budget values to the database.
+  using StoreBudgetCallback = base::Callback<void(bool success)>;
+
+  using CacheCallback = base::Callback<void(bool success)>;
 
   void OnDatabaseInit(bool success);
 
@@ -103,7 +106,7 @@ class BudgetDatabase {
   double GetBudget(const GURL& origin) const;
 
   void AddToCache(const GURL& origin,
-                  const AddToCacheCallback& callback,
+                  const CacheCallback& callback,
                   bool success,
                   std::unique_ptr<budget_service::Budget> budget);
 
@@ -113,15 +116,17 @@ class BudgetDatabase {
 
   void SpendBudgetAfterSync(const GURL& origin,
                             double amount,
-                            const StoreBudgetCallback& callback,
+                            const SpendBudgetCallback& callback,
                             bool success);
 
+  void SpendBudgetAfterWrite(const SpendBudgetCallback& callback, bool success);
+
   void WriteCachedValuesToDatabase(const GURL& origin,
                                    const StoreBudgetCallback& callback);
 
-  void SyncCache(const GURL& origin, const SyncCacheCallback& callback);
+  void SyncCache(const GURL& origin, const CacheCallback& callback);
   void SyncLoadedCache(const GURL& origin,
-                       const SyncCacheCallback& callback,
+                       const CacheCallback& callback,
                        bool success);
 
   // Add budget based on engagement with an origin. The method queries for the