Keep a canonical list of shared function infos.

src/compiler.h

Index: src/compiler.h
diff --git a/src/compiler.h b/src/compiler.h
index c90bf91e596c8376062f6c770e03e4273752a47e..a1f97df269c053951b279d691c1c03af74ae846d 100644
--- a/src/compiler.h
+++ b/src/compiler.h
@@ -638,9 +638,8 @@ class Compiler : public AllStatic {
                                                           int source_length);
 
   // Create a shared function info object (the code may be lazily compiled).
-  static Handle<SharedFunctionInfo> BuildFunctionInfo(FunctionLiteral* node,
-                                                      Handle<Script> script,
-                                                      CompilationInfo* outer);
+  static Handle<SharedFunctionInfo> GetSharedFunctionInfo(
+      FunctionLiteral* node, Handle<Script> script, CompilationInfo* outer);
 
   enum ConcurrencyMode { NOT_CONCURRENT, CONCURRENT };