Simplify VirtualMemory by removing unused ReserveAligned method.

runtime/vm/virtual_memory_macos.cc

 // Copyright (c) 2012, the Dart project authors.  Please see the AUTHORS file
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
 #include "vm/globals.h"
 #if defined(TARGET_OS_MACOS)
 
 #include "vm/virtual_memory.h"
 
 #include <sys/mman.h>  // NOLINT
@@ skipping 10 matching lines @@
 #define MAP_FAILED reinterpret_cast<void*>(-1)
 
 uword VirtualMemory::page_size_ = 0;
 
 
 void VirtualMemory::InitOnce() {
   page_size_ = getpagesize();
 }
 
 
-VirtualMemory* VirtualMemory::Reserve(intptr_t size) {
+VirtualMemory* VirtualMemory::ReserveInternal(intptr_t size) {
   ASSERT((size & (PageSize() - 1)) == 0);
   void* address = mmap(NULL, size, PROT_NONE,
                        MAP_PRIVATE | MAP_ANON | MAP_NORESERVE,
                        -1, 0);
   if (address == MAP_FAILED) {
     return NULL;
   }
   MemoryRegion region(address, size);
-  return new VirtualMemory(region, NULL);
+  return new VirtualMemory(region);
 }
 
 
 static void unmap(void* address, intptr_t size) {
   if (size == 0) {
     return;
   }
 
   if (munmap(address, size) != 0) {
     FATAL("munmap failed\n");
   }
 }
 
 
 VirtualMemory::~VirtualMemory() {
-  unmap(address(), size());
+  unmap(address(), reserved_size_);
 }
 
 
 void VirtualMemory::FreeSubSegment(void* address, intptr_t size) {
   unmap(address, size);
+  return true;
 }
 
 
 bool VirtualMemory::Commit(uword addr, intptr_t size, bool executable) {
   ASSERT(Contains(addr));
   ASSERT(Contains(addr + size) || (addr + size == end()));
   int prot = PROT_READ | PROT_WRITE | (executable ? PROT_EXEC : 0);
   void* address = mmap(reinterpret_cast<void*>(addr), size, prot,
                        MAP_PRIVATE | MAP_ANON | MAP_FIXED,
                        -1, 0);
@@ skipping 27 matching lines @@
       break;
   }
   return (mprotect(reinterpret_cast<void*>(page_address),
                    end_address - page_address,
                    prot) == 0);
 }
 
 }  // namespace dart
 
 #endif  // defined(TARGET_OS_MACOS)