[Mac] Fix @rpath for Content Shell Helper.

Tbr: avi@chromium.org
Bug: 964486, 958976
Change-Id: Ib178de301ee4b4c4b381135a7a5c8a0faadc08a6
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1618172
Commit-Queue: Robert Sesek <rsesek@chromium.org>
Reviewed-by: Mark Mentovai <mark@chromium.org>
Cr-Commit-Position: refs/heads/master@{#661068}

content/shell/BUILD.gn

@@ -835,10 +835,12 @@ if (is_mac) {
       "//sandbox/mac:seatbelt",
     ]
     ldflags = [
-      # The helper is in Content Shell.app/Contents/Frameworks/Content Shell Helper.app/Contents/MacOS/
+      # The helper is in Content Shell.app/Contents/Frameworks/
+      #     Content Shell Framework.framework/Versions/C/Helpers/
+      #     Content Shell Helper.app/Contents/MacOS/
       # so set rpath up to the base.
       "-rpath",
-      "@executable_path/../../../../../..",
+      "@executable_path/../../../../../../../../../..",
     ]
     info_plist_target = ":content_shell_helper_plist"
   }