[ios] Remove IDC_BACK and IDC_FORWARD

ios/chrome/browser/ui/key_commands_provider.mm

Index: ios/chrome/browser/ui/key_commands_provider.mm
diff --git a/ios/chrome/browser/ui/key_commands_provider.mm b/ios/chrome/browser/ui/key_commands_provider.mm
index 6473ddce21a4ef1ed26d65e2c8a4643c56f9f972..f303c71bd9048ad2199e3c244e42b9f45d96eb14 100644
--- a/ios/chrome/browser/ui/key_commands_provider.mm
+++ b/ios/chrome/browser/ui/key_commands_provider.mm
@@ -39,22 +39,36 @@
   const BOOL hasTabs = [consumer tabsCount] > 0;
 
   const BOOL useRTLLayout = UseRTLLayout();
-  const NSInteger browseLeft = useRTLLayout ? IDC_FORWARD : IDC_BACK;
-  const NSInteger browseRight = useRTLLayout ? IDC_BACK : IDC_FORWARD;
+
+  // Blocks for navigating forward/back.
+  void (^browseLeft)();
+  void (^browseRight)();
+  if (useRTLLayout) {
+    browseLeft = [^{
+      if ([weakConsumer canGoForward])
+        [weakDispatcher goForward];
+    } copy];
+    browseRight = [^{
+      if ([weakConsumer canGoBack])
+        [weakDispatcher goBack];
+    } copy];
+  } else {
+    browseLeft = [^{
+      if ([weakConsumer canGoBack])
+        [weakDispatcher goBack];
+    } copy];
+    browseRight = [^{
+      if ([weakConsumer canGoForward])
+        [weakDispatcher goForward];
+    } copy];
+  }
+
   const int browseLeftDescriptionID = useRTLLayout
                                           ? IDS_IOS_KEYBOARD_HISTORY_FORWARD
                                           : IDS_IOS_KEYBOARD_HISTORY_BACK;
   const int browseRightDescriptionID = useRTLLayout
                                            ? IDS_IOS_KEYBOARD_HISTORY_BACK
                                            : IDS_IOS_KEYBOARD_HISTORY_FORWARD;
-  BOOL (^canBrowseLeft)() = ^() {
-    return useRTLLayout ? [weakConsumer canGoForward]
-                        : [weakConsumer canGoBack];
-  };
-  BOOL (^canBrowseRight)() = ^() {
-    return useRTLLayout ? [weakConsumer canGoBack]
-                        : [weakConsumer canGoForward];
-  };
 
   // Initialize the array of commands with an estimated capacity.
   NSMutableArray* keyCommands = [NSMutableArray arrayWithCapacity:32];
@@ -155,18 +169,14 @@
                                        title:l10n_util::GetNSStringWithFixup(
                                                  browseLeftDescriptionID)
                                       action:^{
-                                        if (canBrowseLeft()) {
-                                          execute(browseLeft);
-                                        }
+                                        browseLeft();
                                       }],
         [UIKeyCommand cr_keyCommandWithInput:UIKeyInputRightArrow
                                modifierFlags:UIKeyModifierCommand
                                        title:l10n_util::GetNSStringWithFixup(
                                                  browseRightDescriptionID)
                                       action:^{
-                                        if (canBrowseRight()) {
-                                          execute(browseRight);
-                                        }
+                                        browseRight();
                                       }],
       ]];
     }
@@ -225,17 +235,13 @@
                              modifierFlags:UIKeyModifierCommand
                                      title:nil
                                     action:^{
-                                      if (canBrowseLeft()) {
-                                        execute(browseLeft);
-                                      }
+                                      browseLeft();
                                     }],
       [UIKeyCommand cr_keyCommandWithInput:@"]"
                              modifierFlags:UIKeyModifierCommand
                                      title:nil
                                     action:^{
-                                      if (canBrowseRight()) {
-                                        execute(browseRight);
-                                      }
+                                      browseRight();
                                     }],
       [UIKeyCommand cr_keyCommandWithInput:@"."
                              modifierFlags:UIKeyModifierCommand