Use the physical-pixel space for native IME on linux platform.

ui/base/ime/dummy_text_input_client.cc

 // Copyright 2013 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/base/ime/dummy_text_input_client.h"
 #include "ui/events/event.h"
 #include "ui/gfx/geometry/rect.h"
 
 namespace ui {
 
@@ skipping 47 matching lines @@
 }
 
 int DummyTextInputClient::GetTextInputFlags() const {
   return 0;
 }
 
 bool DummyTextInputClient::CanComposeInline() const {
   return false;
 }
 
+float DummyTextInputClient::GetScaleFactor() const {
+  return 1.0f;
+}
+
 gfx::Rect DummyTextInputClient::GetCaretBounds() const {
   return gfx::Rect();
 }
 
 bool DummyTextInputClient::GetCompositionCharacterBounds(
     uint32_t index,
     gfx::Rect* rect) const {
   return false;
 }
 
@@ skipping 42 matching lines @@
 
 bool DummyTextInputClient::IsTextEditCommandEnabled(
     TextEditCommand command) const {
   return false;
 }
 
 void DummyTextInputClient::SetTextEditCommandForNextKeyEvent(
     TextEditCommand command) {}
 
 }  // namespace ui