[heap] Reland uncommit unused large object page memory.

src/base/platform/platform-win32.cc

 // Copyright 2012 the V8 project authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 // Platform-specific code for Win32.
 
 // Secure API functions are not available using MinGW with msvcrt.dll
 // on Windows XP. Make sure MINGW_HAS_SECURE_API is not defined to
 // disable definition of secure API functions in standard headers that
 // would conflict with our own implementation.
@@ skipping 1272 matching lines @@
     return false;
   }
   return true;
 }
 
 
 bool VirtualMemory::UncommitRegion(void* base, size_t size) {
   return VirtualFree(base, size, MEM_DECOMMIT) != 0;
 }
 
+bool VirtualMemory::ReleasePartialRegion(void* base, size_t size,
+                                         void* free_start, size_t free_size) {
+  return VirtualFree(free_start, free_size, MEM_DECOMMIT) != 0;
+}
 
 bool VirtualMemory::ReleaseRegion(void* base, size_t size) {
   return VirtualFree(base, 0, MEM_RELEASE) != 0;
 }
 
 
 bool VirtualMemory::HasLazyCommits() {
   // TODO(alph): implement for the platform.
   return false;
 }
@@ skipping 90 matching lines @@
 
 
 void Thread::SetThreadLocal(LocalStorageKey key, void* value) {
   BOOL result = TlsSetValue(static_cast<DWORD>(key), value);
   USE(result);
   DCHECK(result);
 }
 
 }  // namespace base
 }  // namespace v8