Add haptic feedback for swipe-to-go-back.

ios/chrome/browser/ui/uikit_ui_util.mm

Index: ios/chrome/browser/ui/uikit_ui_util.mm
diff --git a/ios/chrome/browser/ui/uikit_ui_util.mm b/ios/chrome/browser/ui/uikit_ui_util.mm
index 381ffc198c98e5f63670977d94d4ca0e3c0caa78..957ed1e79ce618ff22521cf7f0afda61c020ce0f 100644
--- a/ios/chrome/browser/ui/uikit_ui_util.mm
+++ b/ios/chrome/browser/ui/uikit_ui_util.mm
@@ -12,8 +12,10 @@
 #import <UIKit/UIKit.h>
 #include <cmath>
 
+#include "base/ios/ios_util.h"
 #include "base/logging.h"
 #include "base/mac/foundation_util.h"
+#include "base/mac/scoped_nsobject.h"
 #include "ios/chrome/browser/experimental_flags.h"
 #include "ios/chrome/browser/ui/rtl_geometry.h"
 #include "ios/chrome/browser/ui/ui_util.h"
@@ -660,3 +662,23 @@ UIResponder* GetFirstResponder() {
   gFirstResponder = nil;
   return firstResponder;
 }
+
+// On iOS10 and above, trigger a haptic vibration for the user selecting an
+// action. This is a no-op for devices that do not support it.
+void TriggerHapticFeedbackForAction() {
+  if (base::ios::IsRunningOnIOS10OrLater()) {
+    base::scoped_nsobject<UIImpactFeedbackGenerator> generator(

[rohitrao (ping after 24h), 2017/02/23 16:15:54]

This file is ARC, so you shouldn't need to use the scoped_nsobject.

[pink (ping after 24hrs), 2017/02/23 16:22:02]

Done.

+        [[UIImpactFeedbackGenerator alloc] init]);
+    [generator impactOccurred];
+  }
+}
+
+// On iOS10 and above, trigger a haptic vibration for the change in selection.
+// This is a no-op for devices that do not support it.
+void TriggerHapticFeedbackForSelectionChange() {
+  if (base::ios::IsRunningOnIOS10OrLater()) {
+    base::scoped_nsobject<UISelectionFeedbackGenerator> generator(
+        [[UISelectionFeedbackGenerator alloc] init]);
+    [generator selectionChanged];
+  }
+}