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

chrome/browser/web_resource/notification_promo.cc

Index: chrome/browser/web_resource/notification_promo.cc
diff --git a/chrome/browser/web_resource/notification_promo.cc b/chrome/browser/web_resource/notification_promo.cc
index 101643f7817cdee1906bcc8cd6bcee0746b4dc10..bbf36377614c8ee2f03308a0a3ba0859714f9023 100644
--- a/chrome/browser/web_resource/notification_promo.cc
+++ b/chrome/browser/web_resource/notification_promo.cc
@@ -27,8 +27,7 @@
 #include "url/gurl.h"
 
 #if defined(OS_ANDROID)

[Alexei Svitkine (slow), 2013/10/31 14:52:32]

Same comment as for device_info.cc.

[yao, 2013/11/01 14:37:59]

Done.

-#include "base/command_line.h"
-#include "chrome/common/chrome_switches.h"
+#include "chrome/common/device_form_factor.h"
 #endif  // defined(OS_ANDROID)
 
 using content::UserMetricsAction;
@@ -72,9 +71,9 @@ std::string PlatformString() {
 #elif defined(OS_LINUX)
   return "linux";
 #elif defined(OS_ANDROID)
-  const bool isTablet =
-      CommandLine::ForCurrentProcess()->HasSwitch(switches::kTabletUI);
-  return std::string("android-") + (isTablet ? "tablet" : "phone");
+  DeviceFormFactor device = GetDeviceFormFactor();

[Alexei Svitkine (slow), 2013/10/31 14:52:32]

Nit: remove to |form_factor|.

[yao, 2013/11/01 14:37:59]

Done.

+  return (std::string("android-") +
+          (device == DEVICE_FORM_FACTOR_TABLET? "tablet" : "phone"));

[Alexei Svitkine (slow), 2013/10/31 14:52:32]

Nit: Space before ?

[yao, 2013/11/01 14:37:59]

Done.

 #else
   return "none";
 #endif