Move MessagePort implementation from android_webview to content

content/public/android/BUILD.gn

Index: content/public/android/BUILD.gn
diff --git a/content/public/android/BUILD.gn b/content/public/android/BUILD.gn
index a20636bf3256cf8a6ea3046b50016e2b49bb2fde..762d2fef8103eef678212f114485e05c5b95edbf 100644
--- a/content/public/android/BUILD.gn
+++ b/content/public/android/BUILD.gn
@@ -100,6 +100,8 @@ android_library("content_java") {
     "java/src/org/chromium/content/app/SandboxedProcessService7.java",
     "java/src/org/chromium/content/app/SandboxedProcessService8.java",
     "java/src/org/chromium/content/app/SandboxedProcessService9.java",
+    "java/src/org/chromium/content/browser/AppWebMessagePort.java",
+    "java/src/org/chromium/content/browser/AppWebMessagePortService.java",
     "java/src/org/chromium/content/browser/ActivityContentVideoViewEmbedder.java",
     "java/src/org/chromium/content/browser/BackgroundSyncNetworkObserver.java",
     "java/src/org/chromium/content/browser/BindingManager.java",
@@ -134,6 +136,7 @@ android_library("content_java") {
     "java/src/org/chromium/content/browser/PepperPluginManager.java",
     "java/src/org/chromium/content/browser/PopupZoomer.java",
     "java/src/org/chromium/content/browser/PositionObserver.java",
+    "java/src/org/chromium/content/browser/PostMessageSender.java",
     "java/src/org/chromium/content/browser/RenderCoordinates.java",
     "java/src/org/chromium/content/browser/SPenSupport.java",
     "java/src/org/chromium/content/browser/ScreenOrientationProvider.java",
@@ -289,6 +292,7 @@ generate_jni("content_jni_headers") {
   sources = [
     "java/src/org/chromium/content/app/ChildProcessServiceImpl.java",
     "java/src/org/chromium/content/app/ContentMain.java",
+    "java/src/org/chromium/content/browser/AppWebMessagePortService.java",
     "java/src/org/chromium/content/browser/BackgroundSyncNetworkObserver.java",
     "java/src/org/chromium/content/browser/BrowserStartupController.java",
     "java/src/org/chromium/content/browser/ChildProcessLauncher.java",