Disallow non-postive sizes in vector icon views example.

ui/views/examples/vector_example.cc

 // Copyright 2015 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 "ui/views/examples/vector_example.h"
 
 #include "base/files/file_path.h"
 #include "base/files/file_util.h"
 #include "base/macros.h"
 #include "base/strings/string_number_conversions.h"
@@ skipping 79 matching lines @@
       UpdateImage();
       return true;
     }
     return false;
   }
 
   // TextfieldController implementation.
   void ContentsChanged(Textfield* sender,
                        const base::string16& new_contents) override {
     if (sender == size_input_) {
-      if (base::StringToInt(new_contents, &size_))
+      if (base::StringToInt(new_contents, &size_) && (size_ > 0))
         UpdateImage();
       else
         size_input_->SetText(base::string16());
 
       return;
     }
 
     DCHECK_EQ(color_input_, sender);
     if (new_contents.size() != 8u)
       return;
@@ skipping 52 matching lines @@
 
 VectorExample::~VectorExample() {}
 
 void VectorExample::CreateExampleView(View* container) {
   container->SetLayoutManager(new FillLayout());
   container->AddChildView(new VectorIconGallery());
 }
 
 }  // namespace examples
 }  // namespace views