[iOS/GN] Convert .strings file to binary1 plist format.

build/toolchain/mac/BUILD.gn

Index: build/toolchain/mac/BUILD.gn
diff --git a/build/toolchain/mac/BUILD.gn b/build/toolchain/mac/BUILD.gn
index 146744030c2e838f51fe3b71a9adc55c1e20f721..7807746f146f7dbeb49640e1c11fa912a0b3e95a 100644
--- a/build/toolchain/mac/BUILD.gn
+++ b/build/toolchain/mac/BUILD.gn
@@ -276,9 +276,14 @@ template("mac_toolchain") {
     }
 
     tool("copy_bundle_data") {
+      if (is_ios) {
+        _extra_args = "--strings-format=binary1"
+      } else {
+        _extra_args = ""
+      }
       _tool = rebase_path("//build/toolchain/mac/copy_bundle_data.py",
                           root_build_dir)
-      command = "python $_tool {{source}} {{output}}"
+      command = "python $_tool ${_extra_args} {{source}} {{output}}"
       description = "COPY_BUNDLE_DATA {{source}} {{output}}"
       pool = ":bundle_pool($default_toolchain)"
     }