Add a BUILD target and a script to build a public static library for ios/web_view.

ios/web_view/internal/BUILD.gn

Index: ios/web_view/internal/BUILD.gn
diff --git a/ios/web_view/internal/BUILD.gn b/ios/web_view/internal/BUILD.gn
index 61e7e6be99dd502ce5e9c7b9a4d5615863a4660e..3a5c30baa379b848d1804251ac4fe0f56f4bc8b4 100644
--- a/ios/web_view/internal/BUILD.gn
+++ b/ios/web_view/internal/BUILD.gn
@@ -2,7 +2,25 @@
 # Use of this source code is governed by a BSD-style license that can be
 # found in the LICENSE file.
 
-source_set("internal") {
+DEPS = [
+  "//base",
+  "//components/pref_registry",
+  "//components/prefs",
+  "//components/translate/core/browser",
+  "//components/translate/core/common",
+  "//ios/net",
+  "//ios/web",
+  "//ios/web:user_agent",
+  "//ios/web/public/app",
+  "//ios/web_view/internal/translate",
+  "//ios/web_view/public",
+  "//net",
+  "//net:extras",
+  "//ui/base",
+  "//url",
+]
+
+static_library("internal") {
   visibility = [
     "//ios/web_view",
     "//ios/web_view/internal/*",
@@ -27,22 +45,42 @@ source_set("internal") {
     "pref_names.cc",
     "pref_names.h",
   ]
+  deps = DEPS
+  allow_circular_includes_from = [ "//ios/web_view/internal/translate" ]
+}
+
+# A static library which contains all dependencies of "internal".
+# Used to build "web_view_public".
+static_library("deps_complete") {
+  complete_static_lib = true
+  deps = DEPS
+}
+
+# A static library expected to be used by apps outside Chromium code base.
+# This is a complete static library (containing all dependencies),
+# and it doesn't expose internal symbols to reduce risk of symbol conflict.
+#
+# //ios/web_view:web_view_public is an alias of this library.
+#
+# TODO(ichikawa): Support building a universal binary.
+action("web_view_public") {
+  script = "hide_symbols.py"
   deps = [
-    "//base",
-    "//components/pref_registry",
-    "//components/prefs",
-    "//components/translate/core/browser",
-    "//components/translate/core/common",
-    "//ios/net",
-    "//ios/web",
-    "//ios/web:user_agent",
-    "//ios/web/public/app",
-    "//ios/web_view/internal/translate",
-    "//ios/web_view/public",
-    "//net",
-    "//net:extras",
-    "//ui/base",
-    "//url",
+    ":deps_complete",
+    ":internal",
+  ]
+  outputs = [
+    "$target_out_dir/libweb_view_public.a",
+    "$target_out_dir/libweb_view_public.o",
+  ]
+  args = [
+    "--input_lib",
+    rebase_path("$target_out_dir/libinternal.a", root_build_dir),
+    "--deps_lib",
+    rebase_path("$target_out_dir/libdeps_complete.a", root_build_dir),
+    "--output_obj",
+    rebase_path("$target_out_dir/libweb_view_public.o", root_build_dir),
+    "--output_lib",
+    rebase_path("$target_out_dir/libweb_view_public.a", root_build_dir),
   ]
-  allow_circular_includes_from = [ "//ios/web_view/internal/translate" ]
 }