Add assets and copy target for extra ICU data file

Needed for crrev/c/1818876.

Bug: 1006794
Change-Id: I3a15701ed1fbf85cfeba27d127bbb37707e9aca1
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/deps/icu/+/1834464


Reviewed-by: Jungshik Shin <jshin@chromium.org>

BUILD.gn

@@ -1081,6 +1081,14 @@ if (is_android && enable_java_templates) {
       disable_compression = true
     }
   }
+
+  android_assets("icu_extra_assets") {
+    if (icu_use_data_file) {
+      sources = [ "$root_out_dir/icudtl_extra.dat" ]
+      deps = [ ":extra_icudata" ]
+      disable_compression = true
+    }
+  }
 }
 
 if (is_android) {
@@ -1115,6 +1123,11 @@ if (icu_use_data_file) {
       data = [ "$root_out_dir/$data_bundle" ]
     }
   }
+
+  copy("extra_icudata") {
+    sources = [ "//third_party/icu/android_small/icudtl_extra.dat" ]
+    outputs = [ "$root_out_dir/icudtl_extra.dat" ]
+  }
 } else {
   data_assembly = "$target_gen_dir/${data_bundle_prefix}_dat.S"
   inline_data_assembly = "$target_gen_dir/${data_bundle_prefix}_dat.cc"