Remove MemoryCondition::WARNING

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"
 #include "content/browser/memory/memory_coordinator_impl.h"
 #include "content/common/content_export.h"
 
 namespace content {
 
-// MemoryConditionObserver is an internal implementation of MemoryCoordinator
-// which uses a heuristic to determine the current memory condition. The
-// heuristic is:
-// * Compute number of renderers which can be created until the system will
-//   be in a critical state. Call this N.
-//   (See memory_monitor.h for the definition of "critical")
-// * Covert N to memory condition (one of NORMAL/WARNING/CRITICAL) by using some
-//   thresholds and hysteresis.
+// MemoryConditionObserver observes system memory usage and determines the
+// current MemoryCondition. It dispatches the current condition if the condition
+// has changed.
 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.
@@ skipping 19 matching lines @@
   // 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_;
 
-  // 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
-  // that could be started before hitting critical memory pressure.
-  int expected_renderer_size_;
-  // When in a NORMAL condition and the potential number of new renderers drops
-  // below this level, the coordinator will transition to a WARNING condition.
-  int new_renderers_until_warning_;
-  // When in a NORMAL/WARNING state and the potential number of new renderers
-  // drops below this level, the coordinator will transition to a CRITICAL
-  // condition.
-  int new_renderers_until_critical_;
-  // When in a WARNING/CRITICAL condition and the potential number of new
-  // renderers rises above this level, the coordinator will transition to a
-  // NORMAL condition.
-  int new_renderers_back_to_normal_;
-  // When in a CRITICAL condition and the potential number of new renderers
-  // rises above this level, the coordinator will transition to a WARNING
-  // condition.
-  int new_renderers_back_to_warning_;
   // The current interval of checking the amount of free memory.
   base::TimeDelta monitoring_interval_;
   // The value of |monitoring_interval_| when the browser is foregrounded.
   base::TimeDelta monitoring_interval_foregrounded_;
   // The value of |monitoring_interval_| when the browser is backgrounded.
   base::TimeDelta monitoring_interval_backgrounded_;
 
   DISALLOW_COPY_AND_ASSIGN(MemoryConditionObserver);
 };
 
 }  // namespace content
 
 #endif  // CONTENT_BROWSER_MEMORY_MEMORY_CONDITION_OBSERVER_H_