Add flag to experiments to force high DPI mode.

ui/aura/monitor_manager.cc

Index: ui/aura/monitor_manager.cc
diff --git a/ui/aura/monitor_manager.cc b/ui/aura/monitor_manager.cc
index 8cf70bc8e5b8bdf66ca381fa42d7f8e456659e5d..07947492dd0d38046f347b9bf6001f915036e187 100644
--- a/ui/aura/monitor_manager.cc
+++ b/ui/aura/monitor_manager.cc
@@ -6,7 +6,10 @@
 
 #include <stdio.h>
 
+#include "base/command_line.h"
 #include "base/logging.h"
+#include "base/string_number_conversions.h"
+#include "content/public/common/content_switches.h"
 #include "ui/aura/env.h"
 #include "ui/aura/monitor_observer.h"
 #include "ui/aura/root_window.h"
@@ -41,6 +44,17 @@ gfx::Monitor MonitorManager::CreateMonitorFromSpec(const std::string& spec) {
   } else if (use_fullscreen_host_window_) {
     bounds = gfx::Rect(aura::RootWindowHost::GetNativeScreenSize());
   }
+
+  // Setting a default device scale factor overrides the monitor scale factor.
+  if (CommandLine::ForCurrentProcess()->HasSwitch(
+          switches::kDefaultDeviceScaleFactor)) {
+    int default_device_scale_factor;
+    base::StringToInt(CommandLine::ForCurrentProcess()->GetSwitchValueASCII(

[sky, 2012/04/27 19:44:46]

check return value.

[flackr, 2012/04/30 14:05:15]

Done.

+                          switches::kDefaultDeviceScaleFactor),
+                      &default_device_scale_factor);
+    scale = default_device_scale_factor;
+  }
+
   gfx::Monitor monitor(synthesized_monitor_id++, bounds);
   monitor.set_device_scale_factor(scale);
   DVLOG(1) << "Monitor bounds=" << bounds.ToString() << ", scale=" << scale;