Implement clipboard features in views textfield.

views/controls/textfield/native_textfield_views.cc

Index: views/controls/textfield/native_textfield_views.cc
diff --git a/views/controls/textfield/native_textfield_views.cc b/views/controls/textfield/native_textfield_views.cc
index 2a42c5a82749c8a4951972348acddf0ffb962f08..923de0c4e4265f75952dec8a7b711523a374eec9 100644
--- a/views/controls/textfield/native_textfield_views.cc
+++ b/views/controls/textfield/native_textfield_views.cc
@@ -445,6 +445,18 @@ bool NativeTextfieldViews::HandleKeyEvent(const KeyEvent& key_event) {
           cursor_changed = true;
         }
         break;
+      case app::VKEY_X:
+        if (control)
+          text_changed = model_->Cut();
+        break;
+      case app::VKEY_C:
+        if (control)
+          model_->Copy();
+        break;
+      case app::VKEY_V:
+        if (control)
+          text_changed = model_->Paste();
+        break;
       case app::VKEY_RIGHT:
         control ? model_->MoveCursorToNextWord(selection)
             : model_->MoveCursorRight(selection);