Put HashMap class in dart namespace.

runtime/platform/hashmap.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 PLATFORM_HASHMAP_H_
 #define PLATFORM_HASHMAP_H_
 
 #include "platform/globals.h"
 
+namespace dart {

[Ivan Posva, 2013/04/30 15:07:53]

We should NOT pollute the dart namespace from outside the VM code.

[tfarina, 2013/04/30 16:31:03]

What is your argument about leaving it in the global namespace? Did you run the
command line "git grep --files-without-match  "namespace dart"
runtime/platform/"?
Why would runtime/vm be special and only it use dart namespace? runtime/bin uses
dart::bin namespace already.

v8 on the other hand has all its implementation in src/ and the types are inside
v8::internal namespace, while the public api is in include/v8.h and in the v8
namespace.

Søren suggested that we would put this also in dart::platform namespace. Which
would be consistent with dart::bin namespace.

But that is mirror, and I wouldn't worry too much about this anyway.

+
 class HashMap {
  public:
   typedef bool (*MatchFun) (void* key1, void* key2);
 
   static bool SamePointerValue(void* key1, void* key2) {
     return key1 == key2;
   }
 
   // initial_capacity is the size of the initial hash map;
   // it must be a power of 2 (and thus must not be 0).
@@ skipping 46 matching lines @@
   uint32_t occupancy_;
 
   Entry* map_end() const { return map_ + capacity_; }
   Entry* Probe(void* key, uint32_t hash);
   void Initialize(uint32_t capacity);
   void Resize();
 
   friend class IntSet;  // From hashmap_test.cc
 };
 
+}  // namespace dart
+
 #endif  // PLATFORM_HASHMAP_H_