Replace NULL with nullptr

Also fixed some lines that were too long, and a few other minor
details.

Change-Id: I6efba5fb6e03eb5d0a300fddb2a75bf8e2f175cb
diff --git a/runtime/class_linker-inl.h b/runtime/class_linker-inl.h
index 87d1c4c..1428749 100644
--- a/runtime/class_linker-inl.h
+++ b/runtime/class_linker-inl.h
@@ -60,7 +60,7 @@
                                                   mirror::ArtMethod* referrer) {
   mirror::Class* declaring_class = referrer->GetDeclaringClass();
   mirror::String* resolved_string = declaring_class->GetDexCacheStrings()->Get(string_idx);
-  if (UNLIKELY(resolved_string == NULL)) {
+  if (UNLIKELY(resolved_string == nullptr)) {
     StackHandleScope<1> hs(Thread::Current());
     Handle<mirror::DexCache> dex_cache(hs.NewHandle(declaring_class->GetDexCache()));
     const DexFile& dex_file = *dex_cache->GetDexFile();
@@ -92,7 +92,7 @@
   mirror::Class* declaring_class = referrer->GetDeclaringClass();
   mirror::DexCache* dex_cache_ptr = declaring_class->GetDexCache();
   mirror::Class* resolved_type = dex_cache_ptr->GetResolvedType(type_idx);
-  if (UNLIKELY(resolved_type == NULL)) {
+  if (UNLIKELY(resolved_type == nullptr)) {
     StackHandleScope<2> hs(Thread::Current());
     Handle<mirror::DexCache> dex_cache(hs.NewHandle(dex_cache_ptr));
     Handle<mirror::ClassLoader> class_loader(hs.NewHandle(declaring_class->GetClassLoader()));
@@ -146,7 +146,7 @@
                                                    bool is_static) {
   mirror::Class* declaring_class = referrer->GetDeclaringClass();
   ArtField* resolved_field = GetResolvedField(field_idx, declaring_class);
-  if (UNLIKELY(resolved_field == NULL)) {
+  if (UNLIKELY(resolved_field == nullptr)) {
     StackHandleScope<2> hs(Thread::Current());
     Handle<mirror::DexCache> dex_cache(hs.NewHandle(declaring_class->GetDexCache()));
     Handle<mirror::ClassLoader> class_loader(hs.NewHandle(declaring_class->GetClassLoader()));
@@ -196,7 +196,7 @@
   DCHECK(!class_roots_.IsNull());
   mirror::ObjectArray<mirror::Class>* class_roots = class_roots_.Read();
   mirror::Class* klass = class_roots->Get(class_root);
-  DCHECK(klass != NULL);
+  DCHECK(klass != nullptr);
   return klass;
 }