Fix all our unused parameter warnings so we let GCC report them.

There were a couple of genuine bugs here (fixed), plus there's a missing
feature in trace.cc that I've just added a TODO for.

Also note that I haven't touched the compilers; this warning is still
explicitly disabled for that code. I'll do that when there's less going
on in those directories.

Change-Id: Ic3570bf82411a07c7530bfaf1995ac995b9fc00f
diff --git a/src/class_linker.cc b/src/class_linker.cc
index 7b8a02e..c1acab0 100644
--- a/src/class_linker.cc
+++ b/src/class_linker.cc
@@ -1509,7 +1509,7 @@
   DCHECK(!it.HasNext());
 }
 
-void ClassLinker::LoadField(const DexFile& dex_file, const ClassDataItemIterator& it,
+void ClassLinker::LoadField(const DexFile& /*dex_file*/, const ClassDataItemIterator& it,
                             SirtRef<Class>& klass, SirtRef<Field>& dst) {
   uint32_t field_idx = it.GetMemberIndex();
   dst->SetDexFieldIndex(field_idx);
@@ -1951,7 +1951,7 @@
   }
 }
 #else
-static void CheckMethodsHaveGcMaps(Class* klass) {
+static void CheckMethodsHaveGcMaps(Class*) {
 }
 #endif