Avoid std::string allocations for finding an array class.

Introduce ClassLinker::FindArrayClass which performs an array class lookup
given the element/component class. This has a 16 element cache of recently
looked up arrays.
Pass the current thread to ClassLinker Find .. Class routines to avoid calls
to Thread::Current().
Avoid some uses of FindClass in the debugger where WellKnownClasses is a
faster and more compacting GC friendly alternative.

Change-Id: I60e231820b349543a7edb3ceb9cf1ce92db3c843
diff --git a/runtime/object_utils.h b/runtime/object_utils.h
index a981fab..4eac291 100644
--- a/runtime/object_utils.h
+++ b/runtime/object_utils.h
@@ -17,7 +17,7 @@
 #ifndef ART_RUNTIME_OBJECT_UTILS_H_
 #define ART_RUNTIME_OBJECT_UTILS_H_
 
-#include "class_linker-inl.h"
+#include "class_linker.h"
 #include "dex_file.h"
 #include "monitor.h"
 #include "mirror/art_field.h"
@@ -158,10 +158,10 @@
     DCHECK(!klass_->IsPrimitive());
     if (klass_->IsArrayClass()) {
       if (idx == 0) {
-        return GetClassLinker()->FindSystemClass("Ljava/lang/Cloneable;");
+        return GetClassLinker()->FindSystemClass(Thread::Current(), "Ljava/lang/Cloneable;");
       } else {
         DCHECK_EQ(1U, idx);
-        return GetClassLinker()->FindSystemClass("Ljava/io/Serializable;");
+        return GetClassLinker()->FindSystemClass(Thread::Current(), "Ljava/io/Serializable;");
       }
     } else if (klass_->IsProxyClass()) {
       return klass_->GetIfTable()->GetInterface(idx);
@@ -251,7 +251,7 @@
   mirror::Class* GetType(bool resolve = true) SHARED_LOCKS_REQUIRED(Locks::mutator_lock_) {
     uint32_t field_index = field_->GetDexFieldIndex();
     if (UNLIKELY(field_->GetDeclaringClass()->IsProxyClass())) {
-      return GetClassLinker()->FindSystemClass(GetTypeDescriptor());
+      return GetClassLinker()->FindSystemClass(Thread::Current(), GetTypeDescriptor());
     }
     const DexFile& dex_file = GetDexFile();
     const DexFile::FieldId& field_id = dex_file.GetFieldId(field_index);