Move supports-high-dpi flag into registry.

ui/gfx/win/dpi.cc

Index: ui/gfx/win/dpi.cc
diff --git a/ui/gfx/win/dpi.cc b/ui/gfx/win/dpi.cc
index 798e954eb54760eabbe4922ea36cc277448951ef..0c71d43328257306fcb33d4cc49eddee62821046 100644
--- a/ui/gfx/win/dpi.cc
+++ b/ui/gfx/win/dpi.cc
@@ -98,6 +98,21 @@ BOOL SetProcessDPIAwareWrapper() {
     set_process_dpi_aware_func();
 }
 
+const wchar_t kRegistryProfilePath[] = L"SOFTWARE\\Google\\Chrome\\Profile";
+const wchar_t kHighDPISupport[] = L"high-dpi-support";
+
+DWORD ReadRegistryValue(HKEY root, const wchar_t* base_key,
+    const wchar_t* value_name, DWORD default_value) {
+  base::win::RegKey regKey(HKEY_CURRENT_USER,
+                               base_key,
+                               KEY_QUERY_VALUE);
+  DWORD value;
+  if (regKey.Valid() &&
+      regKey.ReadValueDW(value_name,&value) == ERROR_SUCCESS) {
+    return value;
+  }
+  return default_value;
+}
 }  // namespace
 
 namespace gfx {
@@ -137,14 +152,18 @@ float GetDPIScale() {
   return 1.0;
 }
 
+std::wstring ConvertToWString(const std::string& s) {
+  std::wstring result;
+  result.assign(s.begin(),s.end());
+  return result;
+}
+
 bool IsHighDPIEnabled() {
   // 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,
+      ConvertToWString(switches::kHighDPISupport).c_str(),FALSE);
+  return value == 1;
 }
 
 bool IsInHighDPIMode() {
@@ -152,8 +171,9 @@ bool IsInHighDPIMode() {
 }
 
 void EnableHighDPISupport() {
-  if (IsHighDPIEnabled() &&
-      (base::win::GetVersion() < base::win::VERSION_WIN8_1)) {
+  // TODO: Test to see if this changes in Win8.1 - If not, then change
+  // GetUndocumentedDPIScale...
+  if (IsHighDPIEnabled()) {
     if (!SetProcessDpiAwarenessWrapper(PROCESS_SYSTEM_DPI_AWARE)) {
       SetProcessDPIAwareWrapper();
     }