macOS: Fix <select> popup menu position in RTL.

content/browser/renderer_host/webmenurunner_mac.mm

Index: content/browser/renderer_host/webmenurunner_mac.mm
diff --git a/content/browser/renderer_host/webmenurunner_mac.mm b/content/browser/renderer_host/webmenurunner_mac.mm
index 0e189bedd6941e304e4797177054e3bbcad5fd58..a5849161f9062d6e39765c90c92b11f1a50de44a 100644
--- a/content/browser/renderer_host/webmenurunner_mac.mm
+++ b/content/browser/renderer_host/webmenurunner_mac.mm
@@ -120,10 +120,25 @@
   // bad happens.
   [cell selectItemWithTag:index];
 
-  if (rightAligned_ &&
-      [cell respondsToSelector:@selector(setUserInterfaceLayoutDirection:)]) {
-    [cell setUserInterfaceLayoutDirection:
-        NSUserInterfaceLayoutDirectionRightToLeft];
+  if (rightAligned_) {
+    SEL sel = @selector(setUserInterfaceLayoutDirection:);
+    if ([cell respondsToSelector:sel]) {

[Avi (use Gerrit), 2016/11/30 17:25:04]

NSCell has supported this property since 10.6, so it's safe to pull the if() and
always do the call. (I think I put this -respondsToSelector: guard back when we
supported 10.5.)

[tkent, 2016/11/30 23:43:57]

Done.

+      [cell setUserInterfaceLayoutDirection:
+                NSUserInterfaceLayoutDirectionRightToLeft];
+    }
+    // setUserInterfaceLayoutDirection for NSMenu is supported on macOS 10.11+.
+    if ([menu_ respondsToSelector:sel]) {
+      NSUserInterfaceLayoutDirection direction =
+          NSUserInterfaceLayoutDirectionRightToLeft;
+      NSMethodSignature* signature =
+          [NSMenu instanceMethodSignatureForSelector:sel];
+      NSInvocation* invocation =
+          [NSInvocation invocationWithMethodSignature:signature];
+      [invocation setTarget:menu_.get()];
+      [invocation setSelector:sel];
+      [invocation setArgument:&direction atIndex:2];
+      [invocation invoke];
+    }
   }
 
   // When popping up a menu near the Dock, Cocoa restricts the menu