Avoid handle-less fields in ClassLinker::InitializeClass()

There were some handle-less fields in a SafeMap across GC points.

Bug: 12687968
Change-Id: Ib8c6527d4e23031f1d0074fa11d8f85499b68340
diff --git a/runtime/dex_file.cc b/runtime/dex_file.cc
index ddc2147..db1a044 100644
--- a/runtime/dex_file.cc
+++ b/runtime/dex_file.cc
@@ -1200,7 +1200,7 @@
 }
 
 template<bool kTransactionActive>
-void EncodedStaticFieldValueIterator::ReadValueToField(mirror::ArtField* field) const {
+void EncodedStaticFieldValueIterator::ReadValueToField(Handle<mirror::ArtField> field) const {
   switch (type_) {
     case kBoolean: field->SetBoolean<kTransactionActive>(field->GetDeclaringClass(), jval_.z); break;
     case kByte:    field->SetByte<kTransactionActive>(field->GetDeclaringClass(), jval_.b); break;
@@ -1227,8 +1227,8 @@
     default: UNIMPLEMENTED(FATAL) << ": type " << type_;
   }
 }
-template void EncodedStaticFieldValueIterator::ReadValueToField<true>(mirror::ArtField* field) const;
-template void EncodedStaticFieldValueIterator::ReadValueToField<false>(mirror::ArtField* field) const;
+template void EncodedStaticFieldValueIterator::ReadValueToField<true>(Handle<mirror::ArtField> field) const;
+template void EncodedStaticFieldValueIterator::ReadValueToField<false>(Handle<mirror::ArtField> field) const;
 
 CatchHandlerIterator::CatchHandlerIterator(const DexFile::CodeItem& code_item, uint32_t address) {
   handler_.address_ = -1;