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..56bab00321ed5d313e3a420156dc8c446563d83b 100644
--- a/chrome/browser/web_resource/notification_promo.cc
+++ b/chrome/browser/web_resource/notification_promo.cc
@@ -24,13 +24,9 @@
 #include "components/user_prefs/pref_registry_syncable.h"
 #include "content/public/browser/user_metrics.h"
 #include "net/base/url_util.h"
+#include "ui/base/device_form_factor.h"
 #include "url/gurl.h"
 
-#if defined(OS_ANDROID)
-#include "base/command_line.h"
-#include "chrome/common/chrome_switches.h"
-#endif  // defined(OS_ANDROID)
-
 using content::UserMetricsAction;
 
 namespace {
@@ -63,8 +59,9 @@ std::string PlatformString() {
   return "win";
 #elif defined(OS_IOS)
   // TODO(noyau): add iOS-specific implementation
-  const bool isTablet = false;
-  return std::string("ios-") + (isTablet ? "tablet" : "phone");
+  DeviceFormFactor form_factor = GetDeviceFormFactor();
+  return std::string("ios-") +
+      (form_factor == DEVICE_FORM_FACTOR_TABLET ? "tablet" : "phone");
 #elif defined(OS_MACOSX)
   return "mac";
 #elif defined(OS_CHROMEOS)
@@ -72,9 +69,9 @@ 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 form_factor = GetDeviceFormFactor();
+  return (std::string("android-") +
+      (form_factor == DEVICE_FORM_FACTOR_TABLET ? "tablet" : "phone"));
 #else
   return "none";
 #endif