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

ui/gfx/dpi.h

Index: ui/gfx/dpi.h
diff --git a/ui/gfx/win/dpi.h b/ui/gfx/dpi.h
similarity index 89%
rename from ui/gfx/win/dpi.h
rename to ui/gfx/dpi.h
index 19f6a579c79e8f9d055127d4797774693aca0336..ae8b36ef33b24d89776fa64ea742159d4898ff99 100644
--- a/ui/gfx/win/dpi.h
+++ b/ui/gfx/dpi.h
@@ -2,8 +2,8 @@
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
-#ifndef UI_GFX_DPI_WIN_H_
-#define UI_GFX_DPI_WIN_H_
+#ifndef UI_GFX_DPI_H_
+#define UI_GFX_DPI_H_
 
 #include "ui/gfx/gfx_export.h"
 #include "ui/gfx/point.h"
@@ -19,26 +19,21 @@ namespace gfx {
 // have no effect.
 GFX_EXPORT void InitDeviceScaleFactor(float scale);
 
-GFX_EXPORT Size GetDPI();
-
-// Gets the scale factor of the display. For example, if the display DPI is
-// 96 then the scale factor is 1.0.
-GFX_EXPORT float GetDPIScale();
-
-// Tests to see if the command line flag "--high-dpi-support" is set.
-GFX_EXPORT bool IsHighDPIEnabled();
-
-GFX_EXPORT bool IsInHighDPIMode();
+GFX_EXPORT float GetDeviceScaleFactor();
 
-GFX_EXPORT void EnableHighDPISupport();
+// Returns true if the global device scale factor has been explicitly set for
+// the process.
+GFX_EXPORT bool IsDeviceScaleFactorSet();
 
 GFX_EXPORT void ForceHighDPISupportForTesting(float scale);
 
-// TODO(kevers|girard):  Move above methods into win namespace.
+GFX_EXPORT bool IsInHighDPIMode();
 
-namespace win {
+GFX_EXPORT Size GetDPI();
 
-GFX_EXPORT float GetDeviceScaleFactor();
+// Gets the scale factor of the display. For example, if the display DPI is
+// 96 then the scale factor is 1.0.
+GFX_EXPORT float GetDPIScale();
 
 GFX_EXPORT Point ScreenToDIPPoint(const Point& pixel_point);
 
@@ -54,18 +49,22 @@ GFX_EXPORT Rect DIPToScreenRect(const Rect& dip_bounds);
 GFX_EXPORT Size ScreenToDIPSize(const Size& size_in_pixels);
 GFX_EXPORT Size DIPToScreenSize(const Size& dip_size);
 
+// Tests to see if the command line flag "--high-dpi-support" is set on Windows,
+// always true on Linux.
+GFX_EXPORT bool IsHighDPIEnabled();
+
+#if defined(OS_WIN)
+namespace win {
+
+GFX_EXPORT void EnableHighDPISupport();
+
 // Win32's GetSystemMetrics uses pixel measures. This function calls
 // GetSystemMetrics for the given |metric|, then converts the result to DIP.
 GFX_EXPORT int GetSystemMetricsInDIP(int metric);
 
-// Returns true if the global device scale factor has been explicitly set for
-// the process.
-GFX_EXPORT bool IsDeviceScaleFactorSet();
-
-GFX_EXPORT extern const wchar_t kRegistryProfilePath[];
-GFX_EXPORT extern const wchar_t kHighDPISupportW[];
-
 }  // namespace win
+#endif  // OS_WIN
+
 }  // namespace gfx
 
-#endif  // UI_GFX_DPI_WIN_H_
+#endif  // UI_GFX_DPI_H_