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

ui/gfx/dpi_win.cc

Index: ui/gfx/dpi_win.cc
diff --git a/ui/gfx/win/dpi.cc b/ui/gfx/dpi_win.cc
similarity index 50%
rename from ui/gfx/win/dpi.cc
rename to ui/gfx/dpi_win.cc
index 2777f7cb01235bb838de9c8e7b42343a1f5f2499..a7f6732ae2d3c284cd83e55c7ca65f6fa1d2c368 100644
--- a/ui/gfx/win/dpi.cc
+++ b/ui/gfx/dpi_win.cc
@@ -1,13 +1,15 @@
-// Copyright (c) 2012 The Chromium Authors. All rights reserved.
+// Copyright 2014 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/gfx/win/dpi.h"
+#include "ui/gfx/dpi.h"
 
 #include <windows.h>
+
+#include "base/logging.h"
+#include "base/win/registry.h"
 #include "base/win/scoped_hdc.h"
 #include "base/win/windows_version.h"
-#include "base/win/registry.h"
 #include "ui/gfx/display.h"
 #include "ui/gfx/point_conversions.h"
 #include "ui/gfx/rect_conversions.h"
@@ -15,32 +17,19 @@
 
 namespace {
 
-int kDefaultDPIX = 96;
-int kDefaultDPIY = 96;
-
-bool force_highdpi_for_testing = false;
-
-BOOL IsProcessDPIAwareWrapper() {
-  typedef BOOL(WINAPI *IsProcessDPIAwarePtr)(VOID);
-  IsProcessDPIAwarePtr is_process_dpi_aware_func =
-      reinterpret_cast<IsProcessDPIAwarePtr>(
-          GetProcAddress(GetModuleHandleA("user32.dll"), "IsProcessDPIAware"));
-  if (is_process_dpi_aware_func)
-    return is_process_dpi_aware_func();
-  return FALSE;
-}
-
-float g_device_scale_factor = 0.0f;
-
-float GetUnforcedDeviceScaleFactor() {
-  // If the global device scale factor is initialized use it. This is to ensure
-  // we use the same scale factor across all callsites. We don't use the
-  // GetDeviceScaleFactor function here because it fires a DCHECK if the
-  // g_device_scale_factor global is 0.
-  if (g_device_scale_factor)
-    return g_device_scale_factor;
-  return static_cast<float>(gfx::GetDPI().width()) /
-      static_cast<float>(kDefaultDPIX);
+DWORD ReadRegistryValue(HKEY root,
+                        const wchar_t* base_key,
+                        const wchar_t* value_name,
+                        DWORD default_value) {
+  base::win::RegKey reg_key(HKEY_CURRENT_USER,
+                            base_key,
+                            KEY_QUERY_VALUE);
+  DWORD value;
+  if (reg_key.Valid() &&
+      reg_key.ReadValueDW(value_name, &value) == ERROR_SUCCESS) {
+    return value;
+  }
+  return default_value;
 }
 
 // Duplicated from Win8.1 SDK ShellScalingApi.h
@@ -89,30 +78,10 @@ BOOL SetProcessDPIAwareWrapper() {
     set_process_dpi_aware_func();
 }
 
-DWORD ReadRegistryValue(HKEY root,
-                        const wchar_t* base_key,
-                        const wchar_t* value_name,
-                        DWORD default_value) {
-  base::win::RegKey reg_key(HKEY_CURRENT_USER,
-                            base_key,
-                            KEY_QUERY_VALUE);
-  DWORD value;
-  if (reg_key.Valid() &&
-      reg_key.ReadValueDW(value_name, &value) == ERROR_SUCCESS) {
-    return value;
-  }
-  return default_value;
-}
-
 }  // namespace
 
 namespace gfx {
 
-void InitDeviceScaleFactor(float scale) {
-  DCHECK_NE(0.0f, scale);
-  g_device_scale_factor = scale;
-}
-
 Size GetDPI() {
   static int dpi_x = 0;
   static int dpi_y = 0;
@@ -130,38 +99,20 @@ Size GetDPI() {
   return Size(dpi_x, dpi_y);
 }
 
-float GetDPIScale() {
-  if (IsHighDPIEnabled()) {
-    if (gfx::Display::HasForceDeviceScaleFactor())
-      return gfx::Display::GetForcedDeviceScaleFactor();
-    float dpi_scale = GetUnforcedDeviceScaleFactor();
-    if (dpi_scale <= 1.25) {
-      // Force 125% and below to 100% scale. We do this to maintain previous
-      // (non-DPI-aware) behavior where only the font size was boosted.
-      dpi_scale = 1.0;
-    }
-    return dpi_scale;
-  }
-  return 1.0;
-}
-
-void ForceHighDPISupportForTesting(float scale) {
-  g_device_scale_factor = scale;
-}
-
 bool IsHighDPIEnabled() {
+  static const wchar_t kRegistryProfilePath[] =
+      L"Software\\Google\\Chrome\\Profile";
+  static const wchar_t kHighDPISupportW[] = L"high-dpi-support";
+
   // Flag stored in HKEY_CURRENT_USER\SOFTWARE\\Google\\Chrome\\Profile,
   // under the DWORD value high-dpi-support.
   // Default is disabled.
   static DWORD value = ReadRegistryValue(
-      HKEY_CURRENT_USER, gfx::win::kRegistryProfilePath,
-      gfx::win::kHighDPISupportW, TRUE);
+      HKEY_CURRENT_USER, kRegistryProfilePath, kHighDPISupportW, TRUE);
   return value != 0;
 }
 
-bool IsInHighDPIMode() {
-  return GetDPIScale() > 1.0;
-}
+namespace win {
 
 void EnableHighDPISupport() {
   if (IsHighDPIEnabled() &&
@@ -170,61 +121,10 @@ void EnableHighDPISupport() {
   }
 }
 
-namespace win {
-
-GFX_EXPORT const wchar_t kRegistryProfilePath[] =
-    L"Software\\Google\\Chrome\\Profile";
-GFX_EXPORT const wchar_t kHighDPISupportW[] = L"high-dpi-support";
-
-float GetDeviceScaleFactor() {
-  DCHECK_NE(0.0f, g_device_scale_factor);
-  return g_device_scale_factor;
-}
-
-Point ScreenToDIPPoint(const Point& pixel_point) {
-  return ToFlooredPoint(ScalePoint(pixel_point,
-                                   1.0f / GetDeviceScaleFactor()));
-}
-
-Point DIPToScreenPoint(const Point& dip_point) {
-  return ToFlooredPoint(ScalePoint(dip_point, GetDeviceScaleFactor()));
-}
-
-Rect ScreenToDIPRect(const Rect& pixel_bounds) {
-  // It's important we scale the origin and size separately. If we instead
-  // calculated the size from the floored origin and ceiled right the size could
-  // vary depending upon where the two points land. That would cause problems
-  // for the places this code is used (in particular mapping from native window
-  // bounds to DIPs).
-  return Rect(ScreenToDIPPoint(pixel_bounds.origin()),
-              ScreenToDIPSize(pixel_bounds.size()));
-}
-
-Rect DIPToScreenRect(const Rect& dip_bounds) {
-  // See comment in ScreenToDIPRect for why we calculate size like this.
-  return Rect(DIPToScreenPoint(dip_bounds.origin()),
-              DIPToScreenSize(dip_bounds.size()));
-}
-
-Size ScreenToDIPSize(const Size& size_in_pixels) {
-  // Always ceil sizes. Otherwise we may be leaving off part of the bounds.
-  return ToCeiledSize(
-      ScaleSize(size_in_pixels, 1.0f / GetDeviceScaleFactor()));
-}
-
-Size DIPToScreenSize(const Size& dip_size) {
-  // Always ceil sizes. Otherwise we may be leaving off part of the bounds.
-  return ToCeiledSize(ScaleSize(dip_size, GetDeviceScaleFactor()));
-}
-
 int GetSystemMetricsInDIP(int metric) {
   return static_cast<int>(GetSystemMetrics(metric) /
       GetDeviceScaleFactor() + 0.5);
 }
 
-bool IsDeviceScaleFactorSet() {
-  return g_device_scale_factor != 0.0f;
-}
-
 }  // namespace win
 }  // namespace gfx