Split memory-related routines out of base/process_util.h into base/process/memory.h.

base/process_util_mac.mm

Index: base/process_util_mac.mm
diff --git a/base/process_util_mac.mm b/base/process_util_mac.mm
index 89b6db42d01479058fce8e9a8ed355d78d045b9a..183463ed003158e7b485bb3ce5ca0ab41d9bd8ba 100644
--- a/base/process_util_mac.mm
+++ b/base/process_util_mac.mm
@@ -38,14 +38,6 @@
 #include "third_party/apple_apsl/CFBase.h"
 #include "third_party/apple_apsl/malloc.h"
 
-#if ARCH_CPU_32_BITS
-#include <dlfcn.h>
-#include <mach-o/nlist.h>
-
-#include "base/threading/thread_local.h"
-#include "third_party/mach_override/mach_override.h"
-#endif  // ARCH_CPU_32_BITS
-
 namespace base {
 
 void RestoreDefaultExceptionHandler() {
@@ -65,679 +57,6 @@ void RestoreDefaultExceptionHandler() {
                            EXCEPTION_DEFAULT, THREAD_STATE_NONE);
 }
 
-
-
-// These are helpers for EnableTerminationOnHeapCorruption, which is a no-op
-// on 64 bit Macs.
-#if ARCH_CPU_32_BITS
-namespace {
-
-// Finds the library path for malloc() and thus the libC part of libSystem,
-// which in Lion is in a separate image.
-const char* LookUpLibCPath() {
-  const void* addr = reinterpret_cast<void*>(&malloc);
-
-  Dl_info info;
-  if (dladdr(addr, &info))
-    return info.dli_fname;
-
-  DLOG(WARNING) << "Could not find image path for malloc()";
-  return NULL;
-}
-
-typedef void(*malloc_error_break_t)(void);
-malloc_error_break_t g_original_malloc_error_break = NULL;
-
-// Returns the function pointer for malloc_error_break. This symbol is declared
-// as __private_extern__ and cannot be dlsym()ed. Instead, use nlist() to
-// get it.
-malloc_error_break_t LookUpMallocErrorBreak() {
-  const char* lib_c_path = LookUpLibCPath();
-  if (!lib_c_path)
-    return NULL;
-
-  // Only need to look up two symbols, but nlist() requires a NULL-terminated
-  // array and takes no count.
-  struct nlist nl[3];
-  bzero(&nl, sizeof(nl));
-
-  // The symbol to find.
-  nl[0].n_un.n_name = const_cast<char*>("_malloc_error_break");
-
-  // A reference symbol by which the address of the desired symbol will be
-  // calculated.
-  nl[1].n_un.n_name = const_cast<char*>("_malloc");
-
-  int rv = nlist(lib_c_path, nl);
-  if (rv != 0 || nl[0].n_type == N_UNDF || nl[1].n_type == N_UNDF) {
-    return NULL;
-  }
-
-  // nlist() returns addresses as offsets in the image, not the instruction
-  // pointer in memory. Use the known in-memory address of malloc()
-  // to compute the offset for malloc_error_break().
-  uintptr_t reference_addr = reinterpret_cast<uintptr_t>(&malloc);
-  reference_addr -= nl[1].n_value;
-  reference_addr += nl[0].n_value;
-
-  return reinterpret_cast<malloc_error_break_t>(reference_addr);
-}
-
-// Combines ThreadLocalBoolean with AutoReset.  It would be convenient
-// to compose ThreadLocalPointer<bool> with base::AutoReset<bool>, but that
-// would require allocating some storage for the bool.
-class ThreadLocalBooleanAutoReset {
- public:
-  ThreadLocalBooleanAutoReset(ThreadLocalBoolean* tlb, bool new_value)
-      : scoped_tlb_(tlb),
-        original_value_(tlb->Get()) {
-    scoped_tlb_->Set(new_value);
-  }
-  ~ThreadLocalBooleanAutoReset() {
-    scoped_tlb_->Set(original_value_);
-  }
-
- private:
-  ThreadLocalBoolean* scoped_tlb_;
-  bool original_value_;
-
-  DISALLOW_COPY_AND_ASSIGN(ThreadLocalBooleanAutoReset);
-};
-
-base::LazyInstance<ThreadLocalBoolean>::Leaky
-    g_unchecked_malloc = LAZY_INSTANCE_INITIALIZER;
-
-// NOTE(shess): This is called when the malloc library noticed that the heap
-// is fubar.  Avoid calls which will re-enter the malloc library.
-void CrMallocErrorBreak() {
-  g_original_malloc_error_break();
-
-  // Out of memory is certainly not heap corruption, and not necessarily
-  // something for which the process should be terminated. Leave that decision
-  // to the OOM killer.  The EBADF case comes up because the malloc library
-  // attempts to log to ASL (syslog) before calling this code, which fails
-  // accessing a Unix-domain socket because of sandboxing.
-  if (errno == ENOMEM || (errno == EBADF && g_unchecked_malloc.Get().Get()))
-    return;
-
-  // A unit test checks this error message, so it needs to be in release builds.
-  char buf[1024] =
-      "Terminating process due to a potential for future heap corruption: "
-      "errno=";
-  char errnobuf[] = {
-    '0' + ((errno / 100) % 10),
-    '0' + ((errno / 10) % 10),
-    '0' + (errno % 10),
-    '\000'
-  };
-  COMPILE_ASSERT(ELAST <= 999, errno_too_large_to_encode);
-  strlcat(buf, errnobuf, sizeof(buf));
-  RAW_LOG(ERROR, buf);
-
-  // Crash by writing to NULL+errno to allow analyzing errno from
-  // crash dump info (setting a breakpad key would re-enter the malloc
-  // library).  Max documented errno in intro(2) is actually 102, but
-  // it really just needs to be "small" to stay on the right vm page.
-  const int kMaxErrno = 256;
-  char* volatile death_ptr = NULL;
-  death_ptr += std::min(errno, kMaxErrno);
-  *death_ptr = '!';
-}
-
-}  // namespace
-#endif  // ARCH_CPU_32_BITS
-
-void EnableTerminationOnHeapCorruption() {
-#if defined(ADDRESS_SANITIZER) || ARCH_CPU_64_BITS
-  // AddressSanitizer handles heap corruption, and on 64 bit Macs, the malloc
-  // system automatically abort()s on heap corruption.
-  return;
-#else
-  // Only override once, otherwise CrMallocErrorBreak() will recurse
-  // to itself.
-  if (g_original_malloc_error_break)
-    return;
-
-  malloc_error_break_t malloc_error_break = LookUpMallocErrorBreak();
-  if (!malloc_error_break) {
-    DLOG(WARNING) << "Could not find malloc_error_break";
-    return;
-  }
-
-  mach_error_t err = mach_override_ptr(
-     (void*)malloc_error_break,
-     (void*)&CrMallocErrorBreak,
-     (void**)&g_original_malloc_error_break);
-
-  if (err != err_none)
-    DLOG(WARNING) << "Could not override malloc_error_break; error = " << err;
-#endif  // defined(ADDRESS_SANITIZER) || ARCH_CPU_64_BITS
-}
-
-// ------------------------------------------------------------------------
-
-namespace {
-
-bool g_oom_killer_enabled;
-
-// Starting with Mac OS X 10.7, the zone allocators set up by the system are
-// read-only, to prevent them from being overwritten in an attack. However,
-// blindly unprotecting and reprotecting the zone allocators fails with
-// GuardMalloc because GuardMalloc sets up its zone allocator using a block of
-// memory in its bss. Explicit saving/restoring of the protection is required.
-//
-// This function takes a pointer to a malloc zone, de-protects it if necessary,
-// and returns (in the out parameters) a region of memory (if any) to be
-// re-protected when modifications are complete. This approach assumes that
-// there is no contention for the protection of this memory.
-void DeprotectMallocZone(ChromeMallocZone* default_zone,
-                         mach_vm_address_t* reprotection_start,
-                         mach_vm_size_t* reprotection_length,
-                         vm_prot_t* reprotection_value) {
-  mach_port_t unused;
-  *reprotection_start = reinterpret_cast<mach_vm_address_t>(default_zone);
-  struct vm_region_basic_info_64 info;
-  mach_msg_type_number_t count = VM_REGION_BASIC_INFO_COUNT_64;
-  kern_return_t result =
-      mach_vm_region(mach_task_self(),
-                     reprotection_start,
-                     reprotection_length,
-                     VM_REGION_BASIC_INFO_64,
-                     reinterpret_cast<vm_region_info_t>(&info),
-                     &count,
-                     &unused);
-  CHECK(result == KERN_SUCCESS);
-
-  result = mach_port_deallocate(mach_task_self(), unused);
-  CHECK(result == KERN_SUCCESS);
-
-  // Does the region fully enclose the zone pointers? Possibly unwarranted
-  // simplification used: using the size of a full version 8 malloc zone rather
-  // than the actual smaller size if the passed-in zone is not version 8.
-  CHECK(*reprotection_start <=
-            reinterpret_cast<mach_vm_address_t>(default_zone));
-  mach_vm_size_t zone_offset = reinterpret_cast<mach_vm_size_t>(default_zone) -
-      reinterpret_cast<mach_vm_size_t>(*reprotection_start);
-  CHECK(zone_offset + sizeof(ChromeMallocZone) <= *reprotection_length);
-
-  if (info.protection & VM_PROT_WRITE) {
-    // No change needed; the zone is already writable.
-    *reprotection_start = 0;
-    *reprotection_length = 0;
-    *reprotection_value = VM_PROT_NONE;
-  } else {
-    *reprotection_value = info.protection;
-    result = mach_vm_protect(mach_task_self(),
-                             *reprotection_start,
-                             *reprotection_length,
-                             false,
-                             info.protection | VM_PROT_WRITE);
-    CHECK(result == KERN_SUCCESS);
-  }
-}
-
-// === C malloc/calloc/valloc/realloc/posix_memalign ===
-
-typedef void* (*malloc_type)(struct _malloc_zone_t* zone,
-                             size_t size);
-typedef void* (*calloc_type)(struct _malloc_zone_t* zone,
-                             size_t num_items,
-                             size_t size);
-typedef void* (*valloc_type)(struct _malloc_zone_t* zone,
-                             size_t size);
-typedef void (*free_type)(struct _malloc_zone_t* zone,
-                          void* ptr);
-typedef void* (*realloc_type)(struct _malloc_zone_t* zone,
-                              void* ptr,
-                              size_t size);
-typedef void* (*memalign_type)(struct _malloc_zone_t* zone,
-                               size_t alignment,
-                               size_t size);
-
-malloc_type g_old_malloc;
-calloc_type g_old_calloc;
-valloc_type g_old_valloc;
-free_type g_old_free;
-realloc_type g_old_realloc;
-memalign_type g_old_memalign;
-
-malloc_type g_old_malloc_purgeable;
-calloc_type g_old_calloc_purgeable;
-valloc_type g_old_valloc_purgeable;
-free_type g_old_free_purgeable;
-realloc_type g_old_realloc_purgeable;
-memalign_type g_old_memalign_purgeable;
-
-void* oom_killer_malloc(struct _malloc_zone_t* zone,
-                        size_t size) {
-#if ARCH_CPU_32_BITS
-  ScopedClearErrno clear_errno;
-#endif  // ARCH_CPU_32_BITS
-  void* result = g_old_malloc(zone, size);
-  if (!result && size)
-    debug::BreakDebugger();
-  return result;
-}
-
-void* oom_killer_calloc(struct _malloc_zone_t* zone,
-                        size_t num_items,
-                        size_t size) {
-#if ARCH_CPU_32_BITS
-  ScopedClearErrno clear_errno;
-#endif  // ARCH_CPU_32_BITS
-  void* result = g_old_calloc(zone, num_items, size);
-  if (!result && num_items && size)
-    debug::BreakDebugger();
-  return result;
-}
-
-void* oom_killer_valloc(struct _malloc_zone_t* zone,
-                        size_t size) {
-#if ARCH_CPU_32_BITS
-  ScopedClearErrno clear_errno;
-#endif  // ARCH_CPU_32_BITS
-  void* result = g_old_valloc(zone, size);
-  if (!result && size)
-    debug::BreakDebugger();
-  return result;
-}
-
-void oom_killer_free(struct _malloc_zone_t* zone,
-                     void* ptr) {
-#if ARCH_CPU_32_BITS
-  ScopedClearErrno clear_errno;
-#endif  // ARCH_CPU_32_BITS
-  g_old_free(zone, ptr);
-}
-
-void* oom_killer_realloc(struct _malloc_zone_t* zone,
-                         void* ptr,
-                         size_t size) {
-#if ARCH_CPU_32_BITS
-  ScopedClearErrno clear_errno;
-#endif  // ARCH_CPU_32_BITS
-  void* result = g_old_realloc(zone, ptr, size);
-  if (!result && size)
-    debug::BreakDebugger();
-  return result;
-}
-
-void* oom_killer_memalign(struct _malloc_zone_t* zone,
-                          size_t alignment,
-                          size_t size) {
-#if ARCH_CPU_32_BITS
-  ScopedClearErrno clear_errno;
-#endif  // ARCH_CPU_32_BITS
-  void* result = g_old_memalign(zone, alignment, size);
-  // Only die if posix_memalign would have returned ENOMEM, since there are
-  // other reasons why NULL might be returned (see
-  // http://opensource.apple.com/source/Libc/Libc-583/gen/malloc.c ).
-  if (!result && size && alignment >= sizeof(void*)
-      && (alignment & (alignment - 1)) == 0) {
-    debug::BreakDebugger();
-  }
-  return result;
-}
-
-void* oom_killer_malloc_purgeable(struct _malloc_zone_t* zone,
-                                  size_t size) {
-#if ARCH_CPU_32_BITS
-  ScopedClearErrno clear_errno;
-#endif  // ARCH_CPU_32_BITS
-  void* result = g_old_malloc_purgeable(zone, size);
-  if (!result && size)
-    debug::BreakDebugger();
-  return result;
-}
-
-void* oom_killer_calloc_purgeable(struct _malloc_zone_t* zone,
-                                  size_t num_items,
-                                  size_t size) {
-#if ARCH_CPU_32_BITS
-  ScopedClearErrno clear_errno;
-#endif  // ARCH_CPU_32_BITS
-  void* result = g_old_calloc_purgeable(zone, num_items, size);
-  if (!result && num_items && size)
-    debug::BreakDebugger();
-  return result;
-}
-
-void* oom_killer_valloc_purgeable(struct _malloc_zone_t* zone,
-                                  size_t size) {
-#if ARCH_CPU_32_BITS
-  ScopedClearErrno clear_errno;
-#endif  // ARCH_CPU_32_BITS
-  void* result = g_old_valloc_purgeable(zone, size);
-  if (!result && size)
-    debug::BreakDebugger();
-  return result;
-}
-
-void oom_killer_free_purgeable(struct _malloc_zone_t* zone,
-                               void* ptr) {
-#if ARCH_CPU_32_BITS
-  ScopedClearErrno clear_errno;
-#endif  // ARCH_CPU_32_BITS
-  g_old_free_purgeable(zone, ptr);
-}
-
-void* oom_killer_realloc_purgeable(struct _malloc_zone_t* zone,
-                                   void* ptr,
-                                   size_t size) {
-#if ARCH_CPU_32_BITS
-  ScopedClearErrno clear_errno;
-#endif  // ARCH_CPU_32_BITS
-  void* result = g_old_realloc_purgeable(zone, ptr, size);
-  if (!result && size)
-    debug::BreakDebugger();
-  return result;
-}
-
-void* oom_killer_memalign_purgeable(struct _malloc_zone_t* zone,
-                                    size_t alignment,
-                                    size_t size) {
-#if ARCH_CPU_32_BITS
-  ScopedClearErrno clear_errno;
-#endif  // ARCH_CPU_32_BITS
-  void* result = g_old_memalign_purgeable(zone, alignment, size);
-  // Only die if posix_memalign would have returned ENOMEM, since there are
-  // other reasons why NULL might be returned (see
-  // http://opensource.apple.com/source/Libc/Libc-583/gen/malloc.c ).
-  if (!result && size && alignment >= sizeof(void*)
-      && (alignment & (alignment - 1)) == 0) {
-    debug::BreakDebugger();
-  }
-  return result;
-}
-
-// === C++ operator new ===
-
-void oom_killer_new() {
-  debug::BreakDebugger();
-}
-
-// === Core Foundation CFAllocators ===
-
-bool CanGetContextForCFAllocator() {
-  return !base::mac::IsOSLaterThanMountainLion_DontCallThis();
-}
-
-CFAllocatorContext* ContextForCFAllocator(CFAllocatorRef allocator) {
-  if (base::mac::IsOSSnowLeopard()) {
-    ChromeCFAllocatorLeopards* our_allocator =
-        const_cast<ChromeCFAllocatorLeopards*>(
-            reinterpret_cast<const ChromeCFAllocatorLeopards*>(allocator));
-    return &our_allocator->_context;
-  } else if (base::mac::IsOSLion() || base::mac::IsOSMountainLion()) {
-    ChromeCFAllocatorLions* our_allocator =
-        const_cast<ChromeCFAllocatorLions*>(
-            reinterpret_cast<const ChromeCFAllocatorLions*>(allocator));
-    return &our_allocator->_context;
-  } else {
-    return NULL;
-  }
-}
-
-CFAllocatorAllocateCallBack g_old_cfallocator_system_default;
-CFAllocatorAllocateCallBack g_old_cfallocator_malloc;
-CFAllocatorAllocateCallBack g_old_cfallocator_malloc_zone;
-
-void* oom_killer_cfallocator_system_default(CFIndex alloc_size,
-                                            CFOptionFlags hint,
-                                            void* info) {
-  void* result = g_old_cfallocator_system_default(alloc_size, hint, info);
-  if (!result)
-    debug::BreakDebugger();
-  return result;
-}
-
-void* oom_killer_cfallocator_malloc(CFIndex alloc_size,
-                                    CFOptionFlags hint,
-                                    void* info) {
-  void* result = g_old_cfallocator_malloc(alloc_size, hint, info);
-  if (!result)
-    debug::BreakDebugger();
-  return result;
-}
-
-void* oom_killer_cfallocator_malloc_zone(CFIndex alloc_size,
-                                         CFOptionFlags hint,
-                                         void* info) {
-  void* result = g_old_cfallocator_malloc_zone(alloc_size, hint, info);
-  if (!result)
-    debug::BreakDebugger();
-  return result;
-}
-
-// === Cocoa NSObject allocation ===
-
-typedef id (*allocWithZone_t)(id, SEL, NSZone*);
-allocWithZone_t g_old_allocWithZone;
-
-id oom_killer_allocWithZone(id self, SEL _cmd, NSZone* zone)
-{
-  id result = g_old_allocWithZone(self, _cmd, zone);
-  if (!result)
-    debug::BreakDebugger();
-  return result;
-}
-
-}  // namespace
-
-void* UncheckedMalloc(size_t size) {
-  if (g_old_malloc) {
-#if ARCH_CPU_32_BITS
-    ScopedClearErrno clear_errno;
-    ThreadLocalBooleanAutoReset flag(g_unchecked_malloc.Pointer(), true);
-#endif  // ARCH_CPU_32_BITS
-    return g_old_malloc(malloc_default_zone(), size);
-  }
-  return malloc(size);
-}
-
-void EnableTerminationOnOutOfMemory() {
-  if (g_oom_killer_enabled)
-    return;
-
-  g_oom_killer_enabled = true;
-
-  // === C malloc/calloc/valloc/realloc/posix_memalign ===
-
-  // This approach is not perfect, as requests for amounts of memory larger than
-  // MALLOC_ABSOLUTE_MAX_SIZE (currently SIZE_T_MAX - (2 * PAGE_SIZE)) will
-  // still fail with a NULL rather than dying (see
-  // http://opensource.apple.com/source/Libc/Libc-583/gen/malloc.c for details).
-  // Unfortunately, it's the best we can do. Also note that this does not affect
-  // allocations from non-default zones.
-
-  CHECK(!g_old_malloc && !g_old_calloc && !g_old_valloc && !g_old_realloc &&
-        !g_old_memalign) << "Old allocators unexpectedly non-null";
-
-  CHECK(!g_old_malloc_purgeable && !g_old_calloc_purgeable &&
-        !g_old_valloc_purgeable && !g_old_realloc_purgeable &&
-        !g_old_memalign_purgeable) << "Old allocators unexpectedly non-null";
-
-#if !defined(ADDRESS_SANITIZER)
-  // Don't do anything special on OOM for the malloc zones replaced by
-  // AddressSanitizer, as modifying or protecting them may not work correctly.
-
-  ChromeMallocZone* default_zone =
-      reinterpret_cast<ChromeMallocZone*>(malloc_default_zone());
-  ChromeMallocZone* purgeable_zone =
-      reinterpret_cast<ChromeMallocZone*>(malloc_default_purgeable_zone());
-
-  mach_vm_address_t default_reprotection_start = 0;
-  mach_vm_size_t default_reprotection_length = 0;
-  vm_prot_t default_reprotection_value = VM_PROT_NONE;
-  DeprotectMallocZone(default_zone,
-                      &default_reprotection_start,
-                      &default_reprotection_length,
-                      &default_reprotection_value);
-
-  mach_vm_address_t purgeable_reprotection_start = 0;
-  mach_vm_size_t purgeable_reprotection_length = 0;
-  vm_prot_t purgeable_reprotection_value = VM_PROT_NONE;
-  if (purgeable_zone) {
-    DeprotectMallocZone(purgeable_zone,
-                        &purgeable_reprotection_start,
-                        &purgeable_reprotection_length,
-                        &purgeable_reprotection_value);
-  }
-
-  // Default zone
-
-  g_old_malloc = default_zone->malloc;
-  g_old_calloc = default_zone->calloc;
-  g_old_valloc = default_zone->valloc;
-  g_old_free = default_zone->free;
-  g_old_realloc = default_zone->realloc;
-  CHECK(g_old_malloc && g_old_calloc && g_old_valloc && g_old_free &&
-        g_old_realloc)
-      << "Failed to get system allocation functions.";
-
-  default_zone->malloc = oom_killer_malloc;
-  default_zone->calloc = oom_killer_calloc;
-  default_zone->valloc = oom_killer_valloc;
-  default_zone->free = oom_killer_free;
-  default_zone->realloc = oom_killer_realloc;
-
-  if (default_zone->version >= 5) {
-    g_old_memalign = default_zone->memalign;
-    if (g_old_memalign)
-      default_zone->memalign = oom_killer_memalign;
-  }
-
-  // Purgeable zone (if it exists)
-
-  if (purgeable_zone) {
-    g_old_malloc_purgeable = purgeable_zone->malloc;
-    g_old_calloc_purgeable = purgeable_zone->calloc;
-    g_old_valloc_purgeable = purgeable_zone->valloc;
-    g_old_free_purgeable = purgeable_zone->free;
-    g_old_realloc_purgeable = purgeable_zone->realloc;
-    CHECK(g_old_malloc_purgeable && g_old_calloc_purgeable &&
-          g_old_valloc_purgeable && g_old_free_purgeable &&
-          g_old_realloc_purgeable)
-        << "Failed to get system allocation functions.";
-
-    purgeable_zone->malloc = oom_killer_malloc_purgeable;
-    purgeable_zone->calloc = oom_killer_calloc_purgeable;
-    purgeable_zone->valloc = oom_killer_valloc_purgeable;
-    purgeable_zone->free = oom_killer_free_purgeable;
-    purgeable_zone->realloc = oom_killer_realloc_purgeable;
-
-    if (purgeable_zone->version >= 5) {
-      g_old_memalign_purgeable = purgeable_zone->memalign;
-      if (g_old_memalign_purgeable)
-        purgeable_zone->memalign = oom_killer_memalign_purgeable;
-    }
-  }
-
-  // Restore protection if it was active.
-
-  if (default_reprotection_start) {
-    kern_return_t result = mach_vm_protect(mach_task_self(),
-                                           default_reprotection_start,
-                                           default_reprotection_length,
-                                           false,
-                                           default_reprotection_value);
-    CHECK(result == KERN_SUCCESS);
-  }
-
-  if (purgeable_reprotection_start) {
-    kern_return_t result = mach_vm_protect(mach_task_self(),
-                                           purgeable_reprotection_start,
-                                           purgeable_reprotection_length,
-                                           false,
-                                           purgeable_reprotection_value);
-    CHECK(result == KERN_SUCCESS);
-  }
-#endif
-
-  // === C malloc_zone_batch_malloc ===
-
-  // batch_malloc is omitted because the default malloc zone's implementation
-  // only supports batch_malloc for "tiny" allocations from the free list. It
-  // will fail for allocations larger than "tiny", and will only allocate as
-  // many blocks as it's able to from the free list. These factors mean that it
-  // can return less than the requested memory even in a non-out-of-memory
-  // situation. There's no good way to detect whether a batch_malloc failure is
-  // due to these other factors, or due to genuine memory or address space
-  // exhaustion. The fact that it only allocates space from the "tiny" free list
-  // means that it's likely that a failure will not be due to memory exhaustion.
-  // Similarly, these constraints on batch_malloc mean that callers must always
-  // be expecting to receive less memory than was requested, even in situations
-  // where memory pressure is not a concern. Finally, the only public interface
-  // to batch_malloc is malloc_zone_batch_malloc, which is specific to the
-  // system's malloc implementation. It's unlikely that anyone's even heard of
-  // it.
-
-  // === C++ operator new ===
-
-  // Yes, operator new does call through to malloc, but this will catch failures
-  // that our imperfect handling of malloc cannot.
-
-  std::set_new_handler(oom_killer_new);
-
-#ifndef ADDRESS_SANITIZER
-  // === Core Foundation CFAllocators ===
-
-  // This will not catch allocation done by custom allocators, but will catch
-  // all allocation done by system-provided ones.
-
-  CHECK(!g_old_cfallocator_system_default && !g_old_cfallocator_malloc &&
-        !g_old_cfallocator_malloc_zone)
-      << "Old allocators unexpectedly non-null";
-
-  bool cf_allocator_internals_known = CanGetContextForCFAllocator();
-
-  if (cf_allocator_internals_known) {
-    CFAllocatorContext* context =
-        ContextForCFAllocator(kCFAllocatorSystemDefault);
-    CHECK(context) << "Failed to get context for kCFAllocatorSystemDefault.";
-    g_old_cfallocator_system_default = context->allocate;
-    CHECK(g_old_cfallocator_system_default)
-        << "Failed to get kCFAllocatorSystemDefault allocation function.";
-    context->allocate = oom_killer_cfallocator_system_default;
-
-    context = ContextForCFAllocator(kCFAllocatorMalloc);
-    CHECK(context) << "Failed to get context for kCFAllocatorMalloc.";
-    g_old_cfallocator_malloc = context->allocate;
-    CHECK(g_old_cfallocator_malloc)
-        << "Failed to get kCFAllocatorMalloc allocation function.";
-    context->allocate = oom_killer_cfallocator_malloc;
-
-    context = ContextForCFAllocator(kCFAllocatorMallocZone);
-    CHECK(context) << "Failed to get context for kCFAllocatorMallocZone.";
-    g_old_cfallocator_malloc_zone = context->allocate;
-    CHECK(g_old_cfallocator_malloc_zone)
-        << "Failed to get kCFAllocatorMallocZone allocation function.";
-    context->allocate = oom_killer_cfallocator_malloc_zone;
-  } else {
-    NSLog(@"Internals of CFAllocator not known; out-of-memory failures via "
-        "CFAllocator will not result in termination. http://crbug.com/45650");
-  }
-#endif
-
-  // === Cocoa NSObject allocation ===
-
-  // Note that both +[NSObject new] and +[NSObject alloc] call through to
-  // +[NSObject allocWithZone:].
-
-  CHECK(!g_old_allocWithZone)
-      << "Old allocator unexpectedly non-null";
-
-  Class nsobject_class = [NSObject class];
-  Method orig_method = class_getClassMethod(nsobject_class,
-                                            @selector(allocWithZone:));
-  g_old_allocWithZone = reinterpret_cast<allocWithZone_t>(
-      method_getImplementation(orig_method));
-  CHECK(g_old_allocWithZone)
-      << "Failed to get allocWithZone allocation function.";
-  method_setImplementation(orig_method,
-                           reinterpret_cast<IMP>(oom_killer_allocWithZone));
-}
-
 ProcessId GetParentProcessId(ProcessHandle process) {
   struct kinfo_proc info;
   size_t length = sizeof(struct kinfo_proc);