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/entrypoints/jni/jni_entrypoints.cc b/runtime/entrypoints/jni/jni_entrypoints.cc
index 2752407..a68eeeb 100644
--- a/runtime/entrypoints/jni/jni_entrypoints.cc
+++ b/runtime/entrypoints/jni/jni_entrypoints.cc
@@ -34,15 +34,15 @@
   Locks::mutator_lock_->AssertNotHeld(self);  // We come here as Native.
   ScopedObjectAccess soa(self);
 
-  mirror::ArtMethod* method = self->GetCurrentMethod(NULL);
-  DCHECK(method != NULL);
+  mirror::ArtMethod* method = self->GetCurrentMethod(nullptr);
+  DCHECK(method != nullptr);
 
-  // Lookup symbol address for method, on failure we'll return NULL with an exception set,
+  // Lookup symbol address for method, on failure we'll return null with an exception set,
   // otherwise we return the address of the method we found.
   void* native_code = soa.Vm()->FindCodeForNativeMethod(method);
-  if (native_code == NULL) {
+  if (native_code == nullptr) {
     DCHECK(self->IsExceptionPending());
-    return NULL;
+    return nullptr;
   } else {
     // Register so that future calls don't come here
     method->RegisterNative(native_code, false);