[iOS][Settings] Adds IsSmallDevice method to UI Util

This CL adds a method to UI Util to identify small devices.
A device is considered as a small if its logical width is less than or
equal to 375.

Bug: 922511
Change-Id: I3308d770f2ef502a088743ede9e81dcd0cb698ab
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2554997
Commit-Queue: Ewann Pellé <ewannpv@chromium.org>
Reviewed-by: Gauthier Ambard <gambard@chromium.org>
Cr-Commit-Position: refs/heads/master@{#830969}

ios/chrome/browser/ui/util/ui_util.h

@@ -26,6 +26,11 @@ CGFloat CurrentScreenWidth();
 // Returns true if the device is an iPhone X.
 bool IsIPhoneX();
 
+// Returns true if the device is considered as a small device.
+// TODO(crbug.com/1152730): Define what is called a small device & update this
+// method.
+bool IsSmallDevice();
+
 // Returns the approximate corner radius of the current device.
 CGFloat DeviceCornerRadius();
 

ios/chrome/browser/ui/util/ui_util.mm

@@ -38,6 +38,10 @@ bool IsIPhoneX() {
           (height == 2436 || height == 2688 || height == 1792));
 }
 
+bool IsSmallDevice() {
+  return CurrentScreenWidth() <= 375;
+}
+
 CGFloat DeviceCornerRadius() {
   return IsIPhoneX() ? 40.0 : 0.0;
 }