Enable hidpi on Linux, refactor a bit on Windows to share

ui/base/ime/input_method_win.cc

Index: ui/base/ime/input_method_win.cc
diff --git a/ui/base/ime/input_method_win.cc b/ui/base/ime/input_method_win.cc
index f6bc4c099c6385b550face9d53b80033a5750b35..883f812080ee6b85e97e28f2c6eb9ea60a0a1b25 100644
--- a/ui/base/ime/input_method_win.cc
+++ b/ui/base/ime/input_method_win.cc
@@ -11,7 +11,7 @@
 #include "ui/events/event_constants.h"
 #include "ui/events/event_utils.h"
 #include "ui/events/keycodes/keyboard_codes.h"
-#include "ui/gfx/win/dpi.h"
+#include "ui/gfx/dpi.h"
 #include "ui/gfx/win/hwnd_util.h"
 
 namespace ui {
@@ -158,7 +158,7 @@ void InputMethodWin::OnCaretBoundsChanged(const TextInputClient* client) {
   // Tentatively assume that the returned value is DIP (Density Independent
   // Pixel). See the comment in text_input_client.h and http://crbug.com/360334.
   const gfx::Rect dip_screen_bounds(GetTextInputClient()->GetCaretBounds());
-  const gfx::Rect screen_bounds = gfx::win::DIPToScreenRect(dip_screen_bounds);
+  const gfx::Rect screen_bounds = gfx::DIPToScreenRect(dip_screen_bounds);
 
   HWND attached_window = GetAttachedWindowHandle(client);
   // TODO(ime): see comment in TextInputClient::GetCaretBounds(), this
@@ -537,7 +537,7 @@ LRESULT InputMethodWin::OnQueryCharPosition(IMECHARPOSITION* char_positon) {
       return 0;
     dip_rect = client->GetCaretBounds();
   }
-  const gfx::Rect rect = gfx::win::DIPToScreenRect(dip_rect);
+  const gfx::Rect rect = gfx::DIPToScreenRect(dip_rect);
 
   char_positon->pt.x = rect.x();
   char_positon->pt.y = rect.y();