ART: Move dex structs into own header

Separating out the structs from DexFile allows them to be forward-
declared, which reduces the need to include the dex_file header.

Bug: 119869270
Test: m
Change-Id: I32dde5a632884bca7435cd584b4a81883de2e7b4
diff --git a/runtime/imtable-inl.h b/runtime/imtable-inl.h
index 93346f6..21e3eb1 100644
--- a/runtime/imtable-inl.h
+++ b/runtime/imtable-inl.h
@@ -46,7 +46,7 @@
     }
 
     const DexFile* dex_file = method->GetDexFile();
-    const DexFile::MethodId& method_id = dex_file->GetMethodId(method->GetDexMethodIndex());
+    const dex::MethodId& method_id = dex_file->GetMethodId(method->GetDexMethodIndex());
 
     // Class descriptor for the class component.
     *class_hash = ComputeModifiedUtf8Hash(dex_file->GetMethodDeclaringClassDescriptor(method_id));
@@ -54,7 +54,7 @@
     // Method name for the method component.
     *name_hash = ComputeModifiedUtf8Hash(dex_file->GetMethodName(method_id));
 
-    const DexFile::ProtoId& proto_id = dex_file->GetMethodPrototype(method_id);
+    const dex::ProtoId& proto_id = dex_file->GetMethodPrototype(method_id);
 
     // Read the proto for the signature component.
     uint32_t tmp = ComputeModifiedUtf8Hash(
@@ -63,10 +63,10 @@
     // Mix in the argument types.
     // Note: we could consider just using the shorty. This would be faster, at the price of
     //       potential collisions.
-    const DexFile::TypeList* param_types = dex_file->GetProtoParameters(proto_id);
+    const dex::TypeList* param_types = dex_file->GetProtoParameters(proto_id);
     if (param_types != nullptr) {
       for (size_t i = 0; i != param_types->Size(); ++i) {
-        const DexFile::TypeItem& type = param_types->GetTypeItem(i);
+        const dex::TypeItem& type = param_types->GetTypeItem(i);
         tmp = 31 * tmp + ComputeModifiedUtf8Hash(
             dex_file->GetTypeDescriptor(dex_file->GetTypeId(type.type_idx_)));
       }