Update from https://crrev.com/316786

base/memory/discardable_memory_manager.h

Index: base/memory/discardable_memory_manager.h
diff --git a/base/memory/discardable_memory_manager.h b/base/memory/discardable_memory_manager.h
index 8bf92891a3ea967d897053f138d09030de808e62..43737f82778d942672d1d92f0303a4b802068b06 100644
--- a/base/memory/discardable_memory_manager.h
+++ b/base/memory/discardable_memory_manager.h
@@ -31,10 +31,6 @@ class DiscardableMemoryManagerAllocation {
   // is acquired on the allocation.
   virtual void Purge() = 0;
 
-  // Check if allocated memory is still resident. It is illegal to call this
-  // while a lock is acquired on the allocation.
-  virtual bool IsMemoryResident() const = 0;
-
  protected:
   virtual ~DiscardableMemoryManagerAllocation() {}
 };
@@ -72,9 +68,6 @@ class BASE_EXPORT_PRIVATE DiscardableMemoryManager {
   void SetHardMemoryLimitExpirationTime(
       TimeDelta hard_memory_limit_expiration_time);
 
-  // This will make sure that all purged memory is released to the OS.
-  void ReleaseFreeMemory();
-
   // This will attempt to reduce memory footprint until within soft memory
   // limit. Returns true if there's no need to call this again until allocations
   // have been used.