Fix --hydrogen-stats crashing on null_ptr for shared_info

src/compiler.h

 // Copyright 2012 the V8 project authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #ifndef V8_COMPILER_H_
 #define V8_COMPILER_H_
 
 #include "src/allocation.h"
 #include "src/ast.h"
 #include "src/bailout-reason.h"
@@ skipping 276 matching lines @@
   }
 
   GlobalObject* global_object() const {
     return has_global_object() ? closure()->context()->global_object() : NULL;
   }
 
   // Accessors for the different compilation modes.
   bool IsOptimizing() const { return mode_ == OPTIMIZE; }
   bool IsStub() const { return mode_ == STUB; }
   void SetOptimizing(BailoutId osr_ast_id, Handle<Code> unoptimized) {
-    DCHECK(!shared_info().is_null());
+    DCHECK(has_shared_info());
     SetMode(OPTIMIZE);
     osr_ast_id_ = osr_ast_id;
     unoptimized_code_ = unoptimized;
     optimization_id_ = isolate()->NextOptimizationId();
   }
 
   void SetFunctionType(Type::FunctionType* function_type) {
     function_type_ = function_type;
   }
   Type::FunctionType* function_type() const { return function_type_; }
@@ skipping 393 matching lines @@
   Zone zone_;
   size_t info_zone_start_allocation_size_;
   base::ElapsedTimer timer_;
 
   DISALLOW_COPY_AND_ASSIGN(CompilationPhase);
 };
 
 } }  // namespace v8::internal
 
 #endif  // V8_COMPILER_H_