Switch GetConcurrentlyOptimizedCode to MaybeHandle.

src/compiler.cc

Index: src/compiler.cc
diff --git a/src/compiler.cc b/src/compiler.cc
index 9349ad159bcec998b0adc04d0a43c9deb0e85f56..c8966114bfef377a012dcc688fe40f7cbbd9c481 100644
--- a/src/compiler.cc
+++ b/src/compiler.cc
@@ -1784,8 +1784,8 @@ MaybeHandle<Code> Compiler::GetOptimizedCode(Handle<JSFunction> function,
   return MaybeHandle<Code>();
 }
 
-
-Handle<Code> Compiler::GetConcurrentlyOptimizedCode(OptimizedCompileJob* job) {
+MaybeHandle<Code> Compiler::GetConcurrentlyOptimizedCode(
+    OptimizedCompileJob* job) {
   // Take ownership of compilation info.  Deleting compilation info
   // also tears down the zone and the recompile job.
   base::SmartPointer<CompilationInfo> info(job->info());
@@ -1830,7 +1830,7 @@ Handle<Code> Compiler::GetConcurrentlyOptimizedCode(OptimizedCompileJob* job) {
     info->closure()->ShortPrint();
     PrintF(" because: %s]\n", GetBailoutReason(info->bailout_reason()));
   }
-  return Handle<Code>::null();
+  return MaybeHandle<Code>();
 }