No longer OOM on invalid string length.

src/uri.h

 // Copyright 2013 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 109 matching lines @@
       i += step;
     }
   }
 
   ASSERT(start_index < length);
   Handle<String> first_part =
       isolate->factory()->NewProperSubString(string, 0, start_index);
 
   int dest_position = 0;
   Handle<String> second_part;
+  ASSERT(unescaped_length <= String::kMaxLength);
   if (one_byte) {
     Handle<SeqOneByteString> dest =
         isolate->factory()->NewRawOneByteString(unescaped_length);
+    ASSERT(!dest.is_null());
     DisallowHeapAllocation no_allocation;
     Vector<const Char> vector = GetCharVector<Char>(string);
     for (int i = start_index; i < length; dest_position++) {
       int step;
       dest->SeqOneByteStringSet(dest_position,
                                 UnescapeChar(vector, i, length, &step));
       i += step;
     }
     second_part = dest;
   } else {
     Handle<SeqTwoByteString> dest =
         isolate->factory()->NewRawTwoByteString(unescaped_length);
+    ASSERT(!dest.is_null());
     DisallowHeapAllocation no_allocation;
     Vector<const Char> vector = GetCharVector<Char>(string);
     for (int i = start_index; i < length; dest_position++) {
       int step;
       dest->SeqTwoByteStringSet(dest_position,
                                 UnescapeChar(vector, i, length, &step));
       i += step;
     }
     second_part = dest;
   }
@@ skipping 101 matching lines @@
       if (c >= 256) {
         escaped_length += 6;
       } else if (IsNotEscaped(c)) {
         escaped_length++;
       } else {
         escaped_length += 3;
       }
 
       // We don't allow strings that are longer than a maximal length.
       ASSERT(String::kMaxLength < 0x7fffffff - 6);  // Cannot overflow.
-      if (escaped_length > String::kMaxLength) {
-        AllowHeapAllocation allocate_error_and_return;
-        isolate->ThrowInvalidStringLength();
-        return Handle<String>::null();
-      }
+      if (escaped_length > String::kMaxLength) break;  // Provoke exception.
     }
   }
 
   // No length change implies no change.  Return original string if no change.
   if (escaped_length == length) return string;
 
   Handle<SeqOneByteString> dest =
       isolate->factory()->NewRawOneByteString(escaped_length);
+  RETURN_IF_EMPTY_HANDLE_VALUE(isolate, dest, Handle<String>());
   int dest_position = 0;
 
   { DisallowHeapAllocation no_allocation;
     Vector<const Char> vector = GetCharVector<Char>(string);
     for (int i = 0; i < length; i++) {
       uint16_t c = vector[i];
       if (c >= 256) {
         dest->SeqOneByteStringSet(dest_position, '%');
         dest->SeqOneByteStringSet(dest_position+1, 'u');
         dest->SeqOneByteStringSet(dest_position+2, kHexChars[c >> 12]);
@@ skipping 12 matching lines @@
       }
     }
   }
 
   return dest;
 }
 
 } }  // namespace v8::internal
 
 #endif  // V8_URI_H_