Provide a mechanism for the embedder to set a TotalPhysicalMemory callback function.

include/v8.h

 // Copyright 2012 the V8 project authors. All rights reserved.
 // Redistribution and use in source and binary forms, with or without
 // modification, are permitted provided that the following conditions are
 // met:
 //
 //     * Redistributions of source code must retain the above copyright
 //       notice, this list of conditions and the following disclaimer.
 //     * Redistributions in binary form must reproduce the above
 //       copyright notice, this list of conditions and the following
 //       disclaimer in the documentation and/or other materials provided
@@ skipping 3826 matching lines @@
   enum AllocationAction {
     kAllocationActionAllocate = 1 << 0,
     kAllocationActionFree = 1 << 1,
     kAllocationActionAll = kAllocationActionAllocate | kAllocationActionFree
   };
 
 typedef void (*MemoryAllocationCallback)(ObjectSpace space,
                                          AllocationAction action,
                                          int size);
 
+typedef uint64_t (*TotalPhysicalMemoryCallback)();
+
 // --- Leave Script Callback ---
 typedef void (*CallCompletedCallback)();
 
 // --- Failed Access Check Callback ---
 typedef void (*FailedAccessCheckCallback)(Local<Object> target,
                                           AccessType type,
                                           Local<Value> data);
 
 // --- AllowCodeGenerationFromStrings callbacks ---
 
@@ skipping 603 matching lines @@
 
   /**
    * Enables the host application to provide a mechanism for recording
    * histograms. The CreateHistogram function returns a
    * histogram which will later be passed to the AddHistogramSample
    * function.
    */
   static void SetCreateHistogramFunction(CreateHistogramCallback);
   static void SetAddHistogramSampleFunction(AddHistogramSampleCallback);
 
-  /** Callback function for reporting failed access checks.*/
+  /** Callback function for reporting failed access checks. */
   static void SetFailedAccessCheckCallbackFunction(FailedAccessCheckCallback);
 
   /**
+   * Enables the host application to provide a function which returns the total
+   * amount of physical memory available on the platform.
+   */
+  static void SetTotalPhysicalMemoryFunction(TotalPhysicalMemoryCallback);
+
+  /**
    * Enables the host application to receive a notification before a
    * garbage collection.  Allocations are not allowed in the
    * callback function, you therefore cannot manipulate objects (set
    * or delete properties for example) since it is possible such
    * operations will result in the allocation of objects. It is possible
    * to specify the GCType filter for your callback. But it is not possible to
    * register the same callback function two times with different
    * GCType filters.
    */
   static void AddGCPrologueCallback(
@@ skipping 1973 matching lines @@
  */
 
 
 }  // namespace v8
 
 
 #undef TYPE_CHECK
 
 
 #endif  // V8_H_