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

ios/web_view/BUILD.gn

 # Copyright 2016 The Chromium Authors. All rights reserved.
 # Use of this source code is governed by a BSD-style license that can be
 # found in the LICENSE file.
 
+config("web_view_config") {
+  libs = [
+    "$target_out_dir/libweb_view.a",
+
+    # //ios/web_view depends on sqlite3 provided by iOS.
+    "sqlite3",
+  ]
+}
+
 # Public target that should be used to depend on web_view. Only give access
 # to the web_view public headers while still linking with the implementation.
-group("web_view") {
+#
+# This is a complete static library (containing all dependencies), and it
+# doesn't expose internal symbols to reduce risk of symbol conflict.
+copy("web_view") {
   public_deps = [
     "//ios/web_view/public",
   ]
   deps = [
-    "//ios/web_view/internal",
+    "//ios/web_view/internal:lib_web_view",
   ]
+  sources = [
+    "$target_out_dir/internal/libweb_view.a",
+  ]
+  outputs = [
+    "$target_out_dir/libweb_view.a",
+  ]
+
+  # Lets this target behave like a static_library target i.e., Lets its
+  # dependents link to libweb_view.a.
+  public_configs = [ ":web_view_config" ]
 }