Add an optional source length field to the Extension constructor.

src/objects-inl.h

 // Copyright 2011 the V8 project authors. All rights reserved.
 // Redistribution and use in source and binary forms, with or without
 // modification, are permitted provided that the following conditions are
 // met:
 //
 //     * Redistributions of source code must retain the above copyright
 //       notice, this list of conditions and the following disclaimer.
 //     * Redistributions in binary form must reproduce the above
 //       copyright notice, this list of conditions and the following
 //       disclaimer in the documentation and/or other materials provided
@@ skipping 2358 matching lines @@
   return READ_FIELD(this, kSecondOffset);
 }
 
 
 void ConsString::set_second(String* value, WriteBarrierMode mode) {
   WRITE_FIELD(this, kSecondOffset, value);
   CONDITIONAL_WRITE_BARRIER(GetHeap(), this, kSecondOffset, mode);
 }
 
 
-ExternalAsciiString::Resource* ExternalAsciiString::resource() {
+const ExternalAsciiString::Resource* ExternalAsciiString::resource() {
   return *reinterpret_cast<Resource**>(FIELD_ADDR(this, kResourceOffset));
 }
 
 
 void ExternalAsciiString::set_resource(
-    ExternalAsciiString::Resource* resource) {
-  *reinterpret_cast<Resource**>(FIELD_ADDR(this, kResourceOffset)) = resource;
+    const ExternalAsciiString::Resource* resource) {
+  *reinterpret_cast<const Resource**>(
+      FIELD_ADDR(this, kResourceOffset)) = resource;
 }
 
 
-ExternalTwoByteString::Resource* ExternalTwoByteString::resource() {
+const ExternalTwoByteString::Resource* ExternalTwoByteString::resource() {
   return *reinterpret_cast<Resource**>(FIELD_ADDR(this, kResourceOffset));
 }
 
 
 void ExternalTwoByteString::set_resource(
-    ExternalTwoByteString::Resource* resource) {
-  *reinterpret_cast<Resource**>(FIELD_ADDR(this, kResourceOffset)) = resource;
+    const ExternalTwoByteString::Resource* resource) {
+  *reinterpret_cast<const Resource**>(
+      FIELD_ADDR(this, kResourceOffset)) = resource;
 }
 
 
 void JSFunctionResultCache::MakeZeroSize() {
   set_finger_index(kEntriesIndex);
   set_size(kEntriesIndex);
 }
 
 
 void JSFunctionResultCache::Clear() {
@@ skipping 2235 matching lines @@
 #undef WRITE_INT_FIELD
 #undef READ_SHORT_FIELD
 #undef WRITE_SHORT_FIELD
 #undef READ_BYTE_FIELD
 #undef WRITE_BYTE_FIELD
 
 
 } }  // namespace v8::internal
 
 #endif  // V8_OBJECTS_INL_H_