Minor changes based on the profile while running dart2js compile all.

vm/code_descriptors.h

 // Copyright (c) 2012, 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.
 
 #ifndef VM_CODE_DESCRIPTORS_H_
 #define VM_CODE_DESCRIPTORS_H_
 
 #include "vm/globals.h"
 #include "vm/growable_array.h"
 #include "vm/object.h"
 
 namespace dart {
 
 class DescriptorList : public ZoneAllocated {
  public:
   struct PcDesc {
     intptr_t pc_offset;        // PC offset value of the descriptor.
     PcDescriptors::Kind kind;  // Descriptor kind (kDeopt, kOther).
     intptr_t node_id;          // AST node id.
     intptr_t token_index;      // Token position in source of PC.
     intptr_t try_index;        // Try block index of PC.
   };
 
-  DescriptorList() : list_() {
+  explicit DescriptorList(intptr_t initial_capacity) : list_(initial_capacity) {
   }
   ~DescriptorList() { }
 
   intptr_t Length() const {
     return list_.length();
   }
 
   intptr_t PcOffset(int index) const {
     return list_[index].pc_offset;
   }
@@ skipping 119 matching lines @@
   }
 
  private:
   GrowableArray<struct HandlerDesc> list_;
   DISALLOW_COPY_AND_ASSIGN(ExceptionHandlerList);
 };
 
 }  // namespace dart
 
 #endif  // VM_CODE_DESCRIPTORS_H_