Add cross-platform API to get the form factor of the device

ui/base/ui_base_switches.cc

Index: ui/base/ui_base_switches.cc
diff --git a/ui/base/ui_base_switches.cc b/ui/base/ui_base_switches.cc
index a955933e9045aa3afe78d08f0534b375c81d4187..acb9ccc937964fdc1d16ab37492ceb536c07668a 100644
--- a/ui/base/ui_base_switches.cc
+++ b/ui/base/ui_base_switches.cc
@@ -67,6 +67,11 @@ const char kTouchOptimizedUIDisabled[] = "disabled";
 // Enables touch events on the side bezels.
 const char kTouchSideBezels[] = "touch-side-bezels";
 
+#if defined(OS_ANDROID)
+// Uses the tablet specific UI components when available.
+const char kTabletUI[] = "tablet-ui";
+#endif
+
 #if defined(USE_XI2_MT)
 // The calibration factors given as "<left>,<right>,<top>,<bottom>".
 const char kTouchCalibration[] = "touch-calibration";