[cleanup] Replace 0 and NULL with nullptr for src/ files.

Fixing clang-tidy warning.

Bug: v8:8015
Cq-Include-Trybots: luci.chromium.try:linux_chromium_headless_rel;luci.chromium.try:linux_chromium_rel_ng;master.tryserver.blink:linux_trusty_blink_rel
Change-Id: I5404f0b94c7badce2c59d8eac2c32810f4fa2c3c
Reviewed-on: https://chromium-review.googlesource.com/1224317Reviewed-by: Yang Guo <yangguo@chromium.org>
Commit-Queue: Florian Sattler <sattlerf@google.com>
Cr-Commit-Position: refs/heads/master@{#55914}

src/api.cc

@@ -876,7 +876,7 @@ void RegisteredExtension::UnregisterAll() {
 namespace {
 class ExtensionResource : public String::ExternalOneByteStringResource {
  public:
-  ExtensionResource() : data_(0), length_(0) {}
+  ExtensionResource() : data_(nullptr), length_(0) {}
   ExtensionResource(const char* data, size_t length)
       : data_(data), length_(length) {}
   const char* data() const { return data_; }
@@ -1391,7 +1391,7 @@ static Local<FunctionTemplate> FunctionTemplateNew(
     next_serial_number = isolate->heap()->GetNextTemplateSerialNumber();
   }
   obj->set_serial_number(i::Smi::FromInt(next_serial_number));
-  if (callback != 0) {
+  if (callback != nullptr) {
     Utils::ToLocal(obj)->SetCallHandler(callback, data, side_effect_type);
   }
   obj->set_length(length);
@@ -5955,12 +5955,12 @@ HeapStatistics::HeapStatistics()
       number_of_native_contexts_(0),
       number_of_detached_contexts_(0) {}
 
-HeapSpaceStatistics::HeapSpaceStatistics(): space_name_(0),
-                                            space_size_(0),
-                                            space_used_size_(0),
-                                            space_available_size_(0),
-                                            physical_space_size_(0) { }
-
+HeapSpaceStatistics::HeapSpaceStatistics()
+    : space_name_(nullptr),
+      space_size_(0),
+      space_used_size_(0),
+      space_available_size_(0),
+      physical_space_size_(0) {}
 
 HeapObjectStatistics::HeapObjectStatistics()
     : object_type_(nullptr),

src/base/debug/stack_trace_posix.cc

@@ -104,7 +104,7 @@ void DemangleSymbols(std::string* text) {
     // Try to demangle the mangled symbol candidate.
     int status = 0;
     std::unique_ptr<char, FreeDeleter> demangled_symbol(
-        abi::__cxa_demangle(mangled_symbol.c_str(), nullptr, 0, &status));
+        abi::__cxa_demangle(mangled_symbol.c_str(), nullptr, nullptr, &status));
     if (status == 0) {  // Demangling is successful.
       // Remove the mangled symbol.
       text->erase(mangled_start, mangled_end - mangled_start);

src/d8-posix.cc

@@ -204,7 +204,7 @@ class ExecArgs {
         return;
       }
       delete [] exec_args_[i];
-      exec_args_[i] = 0;
+      exec_args_[i] = nullptr;
     }
   }
   static const unsigned kMaxArgs = 1000;

src/date.cc

@@ -27,7 +27,7 @@ static const char kDaysInMonths[] =
     {31, 28, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31};
 
 DateCache::DateCache()
-    : stamp_(0),
+    : stamp_(nullptr),
       tz_cache_(
 #ifdef V8_INTL_SUPPORT
           FLAG_icu_timezone_data ? new ICUTimezoneCache()

src/gdb-jit.cc

@@ -1838,7 +1838,7 @@ extern "C" {
   // GDB will inspect contents of this descriptor.
   // Static initialization is necessary to prevent GDB from seeing
   // uninitialized descriptor.
-  JITDescriptor __jit_debug_descriptor = { 1, 0, 0, 0 };
+  JITDescriptor __jit_debug_descriptor = {1, 0, nullptr, nullptr};
 
 #ifdef OBJECT_PRINT
   void __gdb_print_v8_object(Object* object) {

src/inspector/string-16.cc

@@ -547,7 +547,7 @@ String16 String16::fromUTF8(const char* stringStart, size_t length) {
   UChar* bufferCurrent = bufferStart;
   const char* stringCurrent = stringStart;
   if (convertUTF8ToUTF16(&stringCurrent, stringStart + length, &bufferCurrent,
-                         bufferCurrent + buffer.size(), 0,
+                         bufferCurrent + buffer.size(), nullptr,
                          true) != conversionOK)
     return String16();
 

src/inspector/v8-regex.h

@@ -20,7 +20,8 @@ class V8Regex {
  public:
   V8Regex(V8InspectorImpl*, const String16&, bool caseSensitive,
           bool multiline = false);
-  int match(const String16&, int startFrom = 0, int* matchLength = 0) const;
+  int match(const String16&, int startFrom = 0,
+            int* matchLength = nullptr) const;
   bool isValid() const { return !m_regex.IsEmpty(); }
   const String16& errorMessage() const { return m_errorMessage; }
 

src/libsampler/sampler.cc

@@ -423,7 +423,7 @@ class SignalHandler {
 
   static void Restore() {
     if (signal_handler_installed_) {
-      sigaction(SIGPROF, &old_signal_handler_, 0);
+      sigaction(SIGPROF, &old_signal_handler_, nullptr);
       signal_handler_installed_ = false;
     }
   }

src/runtime/runtime-strings.cc

@@ -581,7 +581,8 @@ static int CopyCachedOneByteCharsToArray(Heap* heap, const uint8_t* chars,
     elements->set(i, value, mode);
   }
   if (i < length) {
-    static_assert(Smi::kZero == 0, "Can use memset since Smi::kZero is 0");
+    static_assert(Smi::kZero == nullptr,
+                  "Can use memset since Smi::kZero is 0");
     memset(elements->data_start() + i, 0, kPointerSize * (length - i));
   }
 #ifdef DEBUG

src/runtime/runtime-test.cc

@@ -1006,7 +1006,7 @@ RUNTIME_FUNCTION(Runtime_WasmNumInterpretedCalls) {
   DCHECK_EQ(1, args.length());
   HandleScope scope(isolate);
   CONVERT_ARG_HANDLE_CHECKED(WasmInstanceObject, instance, 0);
-  if (!instance->has_debug_info()) return 0;
+  if (!instance->has_debug_info()) return nullptr;
   uint64_t num = instance->debug_info()->NumInterpretedCalls();
   return *isolate->factory()->NewNumberFromSize(static_cast<size_t>(num));
 }

src/snapshot/mksnapshot.cc

@@ -350,7 +350,7 @@ bool RunExtraCode(v8::Isolate* isolate, v8::Local<v8::Context> context,
 }
 
 v8::StartupData CreateSnapshotDataBlob(v8::SnapshotCreator* snapshot_creator,
-                                       const char* script_source = NULL) {
+                                       const char* script_source = nullptr) {
   // Create a new isolate and a new context from scratch, optionally run
   // a script to embed, and serialize to create a snapshot blob.
   v8::StartupData result = {nullptr, 0};

src/zone/zone-allocator.h

@@ -42,7 +42,7 @@ class ZoneAllocator {
   T* address(T& x) const { return &x; }
   const T* address(const T& x) const { return &x; }
 
-  T* allocate(size_t n, const void* hint = 0) {
+  T* allocate(size_t n, const void* hint = nullptr) {
     return static_cast<T*>(zone_->NewArray<T>(static_cast<int>(n)));
   }
   void deallocate(T* p, size_t) { /* noop for Zones */
@@ -103,7 +103,7 @@ class RecyclingZoneAllocator : public ZoneAllocator<T> {
   template <typename U>
   friend class RecyclingZoneAllocator;
 
-  T* allocate(size_t n, const void* hint = 0) {
+  T* allocate(size_t n, const void* hint = nullptr) {
     // Only check top block in free list, since this will be equal to or larger
     // than the other blocks in the free list.
     if (free_list_ && free_list_->size >= n) {