Support lazy parsing of inner functions

src/vector.h

 // Copyright 2014 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_VECTOR_H_
 #define V8_VECTOR_H_
 
 #include <string.h>
 #include <algorithm>
 
@@ skipping 73 matching lines @@
 
   // Releases the array underlying this vector. Once disposed the
   // vector is empty.
   void Dispose() {
     DeleteArray(start_);
     start_ = NULL;
     length_ = 0;
   }
 
   inline Vector<T> operator+(int offset) {
-    DCHECK(offset < length_);
+    DCHECK(offset <= length_);
     return Vector<T>(start_ + offset, length_ - offset);
   }
 
+  inline Vector<T>& operator+=(int offset) {
+    DCHECK(offset <= length_);
+    start_ += offset;
+    length_ -= offset;
+    return *this;
+  }
+
   // Factory method for creating empty vectors.
   static Vector<T> empty() { return Vector<T>(NULL, 0); }
 
   template<typename S>
   static Vector<T> cast(Vector<S> input) {
     return Vector<T>(reinterpret_cast<T*>(input.start()),
                      input.length() * sizeof(S) / sizeof(T));
   }
 
   bool operator==(const Vector<T>& other) const {
@@ skipping 69 matching lines @@
 
 inline Vector<char> MutableCStrVector(char* data, int max) {
   int length = StrLength(data);
   return Vector<char>(data, (length < max) ? length : max);
 }
 
 
 } }  // namespace v8::internal
 
 #endif  // V8_VECTOR_H_