Move supports-high-dpi flag into registry.

ui/gfx/win/dpi.cc

 // Copyright (c) 2012 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 <windows.h>
 #include "base/command_line.h"
 #include "base/win/scoped_hdc.h"
 #include "base/win/windows_version.h"
@@ skipping 80 matching lines @@
 BOOL SetProcessDPIAwareWrapper() {
   typedef BOOL(WINAPI *SetProcessDPIAwarePtr)(VOID);
   SetProcessDPIAwarePtr set_process_dpi_aware_func =
       reinterpret_cast<SetProcessDPIAwarePtr>(
       GetProcAddress(GetModuleHandleA("user32.dll"),
                       "SetProcessDPIAware"));
   return set_process_dpi_aware_func &&
     set_process_dpi_aware_func();
 }
 
+const wchar_t kRegistryProfilePath[] = L"SOFTWARE\\Google\\Chrome\\Profile";

[sky, 2014/02/20 15:48:43]

nit: move constants to top of namespace (right here doesn't make sense since
this function can take any value).

[girard, 2014/02/20 20:20:16]

Done.

+const wchar_t kHighDPISupportW[] = L"high-dpi-support";
+
+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 {
 
 float GetModernUIScale() {
   return GetModernUIScaleWrapper();
 }
 
 void InitDeviceScaleFactor(float scale) {
   DCHECK_NE(0.0f, scale);
@@ skipping 20 matching lines @@
 float GetDPIScale() {
   if (IsHighDPIEnabled()) {
     return gfx::Display::HasForceDeviceScaleFactor() ?
         gfx::Display::GetForcedDeviceScaleFactor() :
         GetUnforcedDeviceScaleFactor();
   }
   return 1.0;
 }
 
 bool IsHighDPIEnabled() {
+  // Flag stored in HKEY_CURRENT_USER\SOFTWARE\\Google\\Chrome\\Profile,
+  // under the DWORD value high-dpi-support.
   // Default is disabled.
-  if (CommandLine::ForCurrentProcess()->HasSwitch(
-      switches::kHighDPISupport)) {
-    return CommandLine::ForCurrentProcess()->GetSwitchValueASCII(
-        switches::kHighDPISupport).compare("1") == 0;
-  }
-  return false;
+  static DWORD value = ReadRegistryValue(
+      HKEY_CURRENT_USER, kRegistryProfilePath,
+      kHighDPISupportW, FALSE);
+  return value == 1;
 }
 
 bool IsInHighDPIMode() {
   return GetDPIScale() > 1.0;
 }
 
 void EnableHighDPISupport() {
   if (IsHighDPIEnabled() &&
-      (base::win::GetVersion() < base::win::VERSION_WIN8_1)) {
-    if (!SetProcessDpiAwarenessWrapper(PROCESS_SYSTEM_DPI_AWARE)) {
-      SetProcessDPIAwareWrapper();
-    }
+      !SetProcessDpiAwarenessWrapper(PROCESS_SYSTEM_DPI_AWARE)) {
+    SetProcessDPIAwareWrapper();
   }
 }
 
 namespace win {
 
 float GetDeviceScaleFactor() {
   DCHECK_NE(0.0f, g_device_scale_factor);
   return g_device_scale_factor;
 }
 
@@ skipping 58 matching lines @@
 
 double GetUndocumentedDPITouchScale() {
   static double scale =
       (base::win::GetVersion() < base::win::VERSION_WIN8_1) ?
       GetUndocumentedDPIScale() : 1.0;
   return scale;
 }
 
 }  // namespace win
 }  // namespace gfx