Merge math function ids and custom call generator ids.

src/x64/stub-cache-x64.cc

Index: src/x64/stub-cache-x64.cc
diff --git a/src/x64/stub-cache-x64.cc b/src/x64/stub-cache-x64.cc
index 530222e64ffa1e7141e192971954e2ae33337c24..63e9769591f2832f91c10b2f41e73a563c601958 100644
--- a/src/x64/stub-cache-x64.cc
+++ b/src/x64/stub-cache-x64.cc
@@ -948,8 +948,8 @@ MaybeObject* CallStubCompiler::CompileCallConstant(Object* object,
   // -----------------------------------
 
   SharedFunctionInfo* function_info = function->shared();
-  if (function_info->HasCustomCallGenerator()) {
-    const int id = function_info->custom_call_generator_id();
+  if (function_info->HasBuiltinFunctionId()) {
+    BuiltinFunctionId id = function_info->builtin_function_id();
     MaybeObject* maybe_result = CompileCustomCall(
         id, object, holder,  NULL, function, name);
     Object* result;
@@ -1830,8 +1830,8 @@ MaybeObject* CallStubCompiler::CompileCallGlobal(JSObject* object,
   // -----------------------------------
 
   SharedFunctionInfo* function_info = function->shared();
-  if (function_info->HasCustomCallGenerator()) {
-    const int id = function_info->custom_call_generator_id();
+  if (function_info->HasBuiltinFunctionId()) {
+    BuiltinFunctionId id = function_info->builtin_function_id();
     MaybeObject* maybe_result = CompileCustomCall(
         id, object, holder, cell, function, name);
     Object* result;