Make closures optimizable by Crankshaft compiler.

src/compiler.h

Index: src/compiler.h
diff --git a/src/compiler.h b/src/compiler.h
index 1176c6941a2c12fb029b0e082a4b6b293bc336c5..68066aa67af0b84330127d50e40f12488cccd288 100644
--- a/src/compiler.h
+++ b/src/compiler.h
@@ -114,7 +114,7 @@ class CompilationInfo BASE_EMBEDDED {
     SetMode(OPTIMIZE);
     osr_ast_id_ = osr_ast_id;
   }
-  void DisableOptimization() { SetMode(NONOPT); }
+  void DisableOptimization();
 
   // Deoptimization support.
   bool HasDeoptimizationSupport() const { return supports_deoptimization_; }
@@ -125,9 +125,7 @@ class CompilationInfo BASE_EMBEDDED {
 
   // Determine whether or not we can adaptively optimize.
   bool AllowOptimize() {
-    return V8::UseCrankshaft() &&
-           !closure_.is_null() &&
-           function_->AllowOptimize();
+    return V8::UseCrankshaft() && !closure_.is_null();
   }
 
  private: