Export all CWV* symbols from the ios/web_view dynamic library.

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.
 
 import("//build/config/ios/ios_sdk.gni")
 import("//build/config/ios/rules.gni")
 import("//tools/grit/repack.gni")
 
 config("config") {
   include_dirs = [
     "internal",
     "public",
   ]
 }
 
 ios_framework_bundle("web_view") {
   output_name = "ChromeWebView"
   info_plist = "Info.plist"
 
   sources = [
     "public/cwv.h",
+    "public/cwv_export.h",

[Hiroshi Ichikawa, 2017/03/28 04:35:02]

I needed to add this here too, otherwise it causes a weird error below. Maybe we
should add all headers to "sources" as well?

$ gn gen //out/Debug-iphonesimulator --check
ERROR at //ios/web_view/public/cwv.h:14:11: Include not allowed.
#include "ios/web_view/public/cwv_export.h"
          ^-------------------------------
It is not in any dependency of
  //ios/web_view:web_view_compile_headers_map
The include file is in the target(s):
  //ios/web_view:web_view_copy_public_headers
  //ios/web_view/public:public
at least one of which should somehow be reachable.

[sdefresne, 2017/03/28 10:29:26]

public_headers are not automatically added to sources. public_headers just
inform the build systems that the headers should be copied into the generated
framework.

[michaeldo, 2017/03/28 17:34:19]

I think it's fine to only have cwv_export.h in sources. none of the other
headers are referenced so they should be fine to leave only in the
public_headers section.

   ]
 
   public_headers = [
     "public/criwv_translate_manager.h",
     "public/cwv.h",
     "public/cwv_delegate.h",
+    "public/cwv_export.h",
     "public/cwv_html_element.h",
     "public/cwv_navigation_action.h",
     "public/cwv_navigation_delegate.h",
     "public/cwv_translate_delegate.h",
     "public/cwv_ui_delegate.h",
     "public/cwv_user_content_controller.h",
     "public/cwv_user_script.h",
     "public/cwv_web_view.h",
     "public/cwv_web_view_configuration.h",
   ]
@@ skipping 49 matching lines @@
   public_deps = [
     ":repack_resources",
   ]
   sources = [
     "$target_gen_dir/web_view_resources.pak",
   ]
   outputs = [
     "{{bundle_resources_dir}}/{{source_file_part}}",
   ]
 }