ART: Clean up ClassLinker

Try to clean up and simplify ClassLinker.

Move dex_lock to Locks. Remove dead code. Move single-use
code to user. Hide implementation details from header.

Test: m test-art-host
Change-Id: I58150fa9c2a9524f8304370270c2197d655cb3a8
diff --git a/runtime/runtime.cc b/runtime/runtime.cc
index 92e00ec..66bb803 100644
--- a/runtime/runtime.cc
+++ b/runtime/runtime.cc
@@ -1736,9 +1736,24 @@
   }
 }
 
+static ArtMethod* CreateRuntimeMethod(ClassLinker* class_linker, LinearAlloc* linear_alloc) {
+  const PointerSize image_pointer_size = class_linker->GetImagePointerSize();
+  const size_t method_alignment = ArtMethod::Alignment(image_pointer_size);
+  const size_t method_size = ArtMethod::Size(image_pointer_size);
+  LengthPrefixedArray<ArtMethod>* method_array = class_linker->AllocArtMethodArray(
+      Thread::Current(),
+      linear_alloc,
+      1);
+  ArtMethod* method = &method_array->At(0, method_size, method_alignment);
+  CHECK(method != nullptr);
+  method->SetDexMethodIndex(DexFile::kDexNoIndex);
+  CHECK(method->IsRuntimeMethod());
+  return method;
+}
+
 ArtMethod* Runtime::CreateImtConflictMethod(LinearAlloc* linear_alloc) {
   ClassLinker* const class_linker = GetClassLinker();
-  ArtMethod* method = class_linker->CreateRuntimeMethod(linear_alloc);
+  ArtMethod* method = CreateRuntimeMethod(class_linker, linear_alloc);
   // When compiling, the code pointer will get set later when the image is loaded.
   const PointerSize pointer_size = GetInstructionSetPointerSize(instruction_set_);
   if (IsAotCompiler()) {
@@ -1759,7 +1774,7 @@
 }
 
 ArtMethod* Runtime::CreateResolutionMethod() {
-  auto* method = GetClassLinker()->CreateRuntimeMethod(GetLinearAlloc());
+  auto* method = CreateRuntimeMethod(GetClassLinker(), GetLinearAlloc());
   // When compiling, the code pointer will get set later when the image is loaded.
   if (IsAotCompiler()) {
     PointerSize pointer_size = GetInstructionSetPointerSize(instruction_set_);
@@ -1771,7 +1786,7 @@
 }
 
 ArtMethod* Runtime::CreateCalleeSaveMethod() {
-  auto* method = GetClassLinker()->CreateRuntimeMethod(GetLinearAlloc());
+  auto* method = CreateRuntimeMethod(GetClassLinker(), GetLinearAlloc());
   PointerSize pointer_size = GetInstructionSetPointerSize(instruction_set_);
   method->SetEntryPointFromQuickCompiledCodePtrSize(nullptr, pointer_size);
   DCHECK_NE(instruction_set_, kNone);