ObjPtr<>-ify ClassTable.

Test: m test-art-host-gtest
Test: testrunner.py --host --optimizing
Bug: 31113334
Change-Id: Ieced7a452d381e5cacbafc91fd5d7672d9d92c30
diff --git a/runtime/class_table.cc b/runtime/class_table.cc
index 58f3674..b7d37e2 100644
--- a/runtime/class_table.cc
+++ b/runtime/class_table.cc
@@ -37,7 +37,7 @@
   return LookupByDescriptor(klass) == klass;
 }
 
-mirror::Class* ClassTable::LookupByDescriptor(ObjPtr<mirror::Class> klass) {
+ObjPtr<mirror::Class> ClassTable::LookupByDescriptor(ObjPtr<mirror::Class> klass) {
   ReaderMutexLock mu(Thread::Current(), lock_);
   TableSlot slot(klass);
   for (ClassSet& class_set : classes_) {
@@ -49,7 +49,9 @@
   return nullptr;
 }
 
-mirror::Class* ClassTable::UpdateClass(const char* descriptor, mirror::Class* klass, size_t hash) {
+ObjPtr<mirror::Class> ClassTable::UpdateClass(const char* descriptor,
+                                              ObjPtr<mirror::Class> klass,
+                                              size_t hash) {
   WriterMutexLock mu(Thread::Current(), lock_);
   // Should only be updating latest table.
   DescriptorHashPair pair(descriptor, hash);
@@ -62,7 +64,7 @@
     }
     LOG(FATAL) << "Updating class not found " << descriptor;
   }
-  mirror::Class* const existing = existing_it->Read();
+  const ObjPtr<mirror::Class> existing = existing_it->Read();
   CHECK_NE(existing, klass) << descriptor;
   CHECK(!existing->IsResolved()) << descriptor;
   CHECK_EQ(klass->GetStatus(), ClassStatus::kResolving) << descriptor;
@@ -113,7 +115,7 @@
   return classes_.back().size();
 }
 
-mirror::Class* ClassTable::Lookup(const char* descriptor, size_t hash) {
+ObjPtr<mirror::Class> ClassTable::Lookup(const char* descriptor, size_t hash) {
   DescriptorHashPair pair(descriptor, hash);
   ReaderMutexLock mu(Thread::Current(), lock_);
   for (ClassSet& class_set : classes_) {