Fix mojo build on android.

mojo/services/public/cpp/view_manager/tests/view_manager_unittest.cc

 // Copyright 2014 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "mojo/services/public/cpp/view_manager/view_manager.h"
 
 #include "base/auto_reset.h"
 #include "base/bind.h"
 #include "base/logging.h"
 #include "mojo/public/cpp/application/application.h"
@@ skipping 181 matching lines @@
       : nodes_(nodes),
         views_(views) {}
 
  private:
   // Overridden from NodeObserver:
   virtual void OnNodeDestroy(
       Node* node,
       NodeObserver::DispositionChangePhase phase) OVERRIDE {
     if (phase != NodeObserver::DISPOSITION_CHANGED)
       return;
-    std::set<Id>::const_iterator it = nodes_->find(node->id());
+    std::set<Id>::iterator it = nodes_->find(node->id());
     if (it != nodes_->end())
       nodes_->erase(it);
     if (CanQuit())
       QuitRunLoop();
   }
 
   // Overridden from ViewObserver:
   virtual void OnViewDestroy(
       View* view,
       ViewObserver::DispositionChangePhase phase) OVERRIDE {
     if (phase != ViewObserver::DISPOSITION_CHANGED)
       return;
-    std::set<Id>::const_iterator it = views_->find(view->id());
+    std::set<Id>::iterator it = views_->find(view->id());
     if (it != views_->end())
       views_->erase(it);
     if (CanQuit())
       QuitRunLoop();
   }
 
   bool CanQuit() {
     return (!nodes_ || nodes_->empty()) && (!views_ || views_->empty());
   }
 
@@ skipping 544 matching lines @@
 
     EXPECT_EQ(node1_in_embedded->children().front(),
               embedded->GetNodeById(node11->id()));
     EXPECT_EQ(node1_in_embedded->children().back(),
               embedded->GetNodeById(node12->id()));
   }
 }
 
 }  // namespace view_manager
 }  // namespace mojo