Add SetLength to GrowableArray and use it in code coverage.

runtime/vm/coverage.cc

 // Copyright (c) 2013, the Dart project authors.  Please see the AUTHORS file
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
 #include "vm/coverage.h"
 
 #include "include/dart_api.h"
 
 #include "vm/compiler.h"
 #include "vm/isolate.h"
 #include "vm/json_stream.h"
 #include "vm/object.h"
 #include "vm/object_store.h"
 
 namespace dart {
 
 DEFINE_FLAG(charp, coverage_dir, NULL,
             "Enable writing coverage data into specified directory.");
 
 
 // map[token_pos] -> line-number.
 static void ComputeTokenPosToLineNumberMap(const Script& script,
                                            GrowableArray<intptr_t>* map) {
   const TokenStream& tkns = TokenStream::Handle(script.tokens());
   const intptr_t len = ExternalTypedData::Handle(tkns.GetStream()).Length();
-  map->Clear();
+  map->SetLength(len);
+#if defined(DEBUG)
   for (intptr_t i = 0; i < len; i++) {
-    map->Add(-1);
+    (*map)[i] = -1;
   }
+#endif
   TokenStream::Iterator tkit(tkns, 0, TokenStream::Iterator::kAllTokens);
   intptr_t cur_line = script.line_offset() + 1;
   while (tkit.CurrentTokenKind() != Token::kEOS) {
     (*map)[tkit.CurrentPosition()] = cur_line;
     if (tkit.CurrentTokenKind() == Token::kNEWLINE) {
       cur_line++;
     }
     tkit.Advance();
   }
 }
@@ skipping 187 matching lines @@
           // functions.
           PrintClass(cls, jsarr);
         }
       }
     }
   }
 }
 
 
 }  // namespace dart