Add fast path to VMClassLoader.findLoadedClass

VMClassLoader.findLoadedClass now calls FindClassInPathClassLoader
as a fast path. Exclusive time results (trace view maps launch):

Before:
nativeFillInStackTrace 1.4%
defineClassNative 1.2%
findLoadedClass 0.2%

After:
nativeFillInStackTrace 0.5%
defineClassNative 0.0%
findLoadedClass 0.9%

(cherry picked from commit 194116c836080de14245a3a7c4617d07b8abf8cf)

Change-Id: I63fd7b4bccb71789e92bd39d1d3f9d0de22535de

1 files changed, 6 insertions, 0 deletions

diff --git a/runtime/class_linker.h b/runtime/class_linker.h
index 7afa6a1d85..11ac326c47 100644
--- a/runtime/class_linker.h
+++ b/runtime/class_linker.h
@@ -76,6 +76,12 @@ class ClassLinker {
                            ConstHandle<mirror::ClassLoader> class_loader)
       SHARED_LOCKS_REQUIRED(Locks::mutator_lock_);
 
+  // Find a class in the path class loader, loading it if necessary.
+  mirror::Class* FindClassInPathClassLoader(ScopedObjectAccessAlreadyRunnable& soa,
+                                            Thread* self, const char* descriptor,
+                                            ConstHandle<mirror::ClassLoader> class_loader)
+      SHARED_LOCKS_REQUIRED(Locks::mutator_lock_);
+
   // Finds a class by its descriptor using the "system" class loader, ie by searching the
   // boot_class_path_.
   mirror::Class* FindSystemClass(Thread* self, const char* descriptor)