NotForReview: Expose the global memory budget (chromium side)

content/browser/memory/memory_condition_observer.h

 // Copyright 2016 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #ifndef CONTENT_BROWSER_MEMORY_MEMORY_CONDITION_OBSERVER_H_
 #define CONTENT_BROWSER_MEMORY_MEMORY_CONDITION_OBSERVER_H_
 
 #include "base/cancelable_callback.h"
 #include "base/single_thread_task_runner.h"
 #include "base/time/time.h"
@@ skipping 12 matching lines @@
 //   thresholds and hysteresis.
 class CONTENT_EXPORT MemoryConditionObserver {
  public:
   // |coordinator| must outlive than this instance.
   MemoryConditionObserver(
       MemoryCoordinatorImpl* coordinator,
       scoped_refptr<base::SingleThreadTaskRunner> task_runner);
   ~MemoryConditionObserver();
 
   // Schedules a task to update memory condition. The task will be executed
-  // after |delay| has passed.
-  void ScheduleUpdateCondition(base::TimeDelta delay);
+  // at a given interval.
+  void ScheduleUpdateCondition(base::TimeDelta interval);
 
  private:
   FRIEND_TEST_ALL_PREFIXES(MemoryCoordinatorImplTest, CalculateNextCondition);
   FRIEND_TEST_ALL_PREFIXES(MemoryCoordinatorImplTest, UpdateCondition);
   FRIEND_TEST_ALL_PREFIXES(MemoryCoordinatorImplTest, ForceSetMemoryCondition);
   FRIEND_TEST_ALL_PREFIXES(MemoryCoordinatorImplTest, DiscardTabUnderCritical);
 
   // Calculates next memory condition from the amount of free memory using
   // a heuristic.
   MemoryCondition CalculateNextCondition();
 
   // Periodically called to update the memory condition.
   void UpdateCondition();
 
   MemoryCoordinatorImpl* coordinator_;
   scoped_refptr<base::SingleThreadTaskRunner> task_runner_;
   base::CancelableClosure update_condition_closure_;
 
+  // Current available free memory provided by MemoryMonitor.
+  int current_available_;
+
+  // The maximum value of available free memory. Used to simulate memory
+  // pressure.
+  int max_available_;
+
   // Sets up parameters for the heuristic.
   void InitializeParameters();
 
   // Validates parameters defined below.
   bool ValidateParameters();
 
   // Parameters to control the heuristic.
 
   // The median size of a renderer on the current platform. This is used to
   // convert the amount of free memory to an expected number of new renderers
@@ skipping 16 matching lines @@
   int new_renderers_back_to_warning_;
   // The interval of checking the amount of free memory.
   base::TimeDelta monitoring_interval_;
 
   DISALLOW_COPY_AND_ASSIGN(MemoryConditionObserver);
 };
 
 }  // namespace content
 
 #endif  // CONTENT_BROWSER_MEMORY_MEMORY_CONDITION_OBSERVER_H_