Enable posting a message from JS to Android webview.

android_webview/android_webview.gyp

Index: android_webview/android_webview.gyp
diff --git a/android_webview/android_webview.gyp b/android_webview/android_webview.gyp
index 3f91264c2b444bdee74005646318e4d7051fa76e..09079afb307ce2b5f03fc11b654fd4bc94326771 100644
--- a/android_webview/android_webview.gyp
+++ b/android_webview/android_webview.gyp
@@ -119,6 +119,7 @@
         '../third_party/WebKit/public/blink.gyp:blink',
         '../ui/gl/gl.gyp:gl',
         '../ui/shell_dialogs/shell_dialogs.gyp:shell_dialogs',
+        '../v8/tools/gyp/v8.gyp:v8',
         '../webkit/common/gpu/webkit_gpu.gyp:webkit_gpu',
         'android_webview_pak',
         'android_webview_version',
@@ -155,6 +156,9 @@
         'browser/aw_javascript_dialog_manager.h',
         'browser/aw_login_delegate.cc',
         'browser/aw_login_delegate.h',
+        'browser/aw_message_port_message_filter.cc',
+        'browser/aw_message_port_message_filter.h',
+        'browser/aw_message_port_service.h',
         'browser/aw_pref_store.cc',
         'browser/aw_pref_store.h',
         'browser/aw_quota_manager_bridge.cc',
@@ -223,6 +227,7 @@
         'common/aw_crash_handler.h',
         'common/aw_hit_test_data.cc',
         'common/aw_hit_test_data.h',
+        'common/aw_message_port_messages.h',
         'common/aw_resource.h',
         'common/aw_switches.cc',
         'common/aw_switches.h',
@@ -242,6 +247,8 @@
         'renderer/aw_content_renderer_client.h',
         'renderer/aw_key_systems.cc',
         'renderer/aw_key_systems.h',
+        'renderer/aw_message_port_client.cc',
+        'renderer/aw_message_port_client.h',
         'renderer/aw_permission_client.cc',
         'renderer/aw_permission_client.h',
         'renderer/aw_render_process_observer.cc',