Remote Assistance on Chrome OS Part III - NativeMessageHost

This CL extracts the NativeMessageHost interface from the NativeMessageProcessHost
A NativeMessageHost hosts a native component, which can be
running in the same process as chrome or in a separate
process.

Committed: https://crrev.com/ba722a2a8ddf967dcadb483ea32d5ad31fc4bdf6
Cr-Commit-Position: refs/heads/master@{#298366}

Review URL: https://codereview.chromium.org/591463003

Cr-Commit-Position: refs/heads/master@{#298579}
diff --git a/chrome/browser/about_flags.cc b/chrome/browser/about_flags.cc
index 4549449..413ff41 100644
--- a/chrome/browser/about_flags.cc
+++ b/chrome/browser/about_flags.cc
@@ -1961,7 +1961,15 @@
     SINGLE_VALUE_TYPE(switches::kEnablePluginPowerSaver)
   },
 #endif
-
+#if defined(OS_CHROMEOS)
+  {
+    "enable-remote-assistance",
+    IDS_FLAGS_ENABLE_REMOTE_ASSISTANCE_NAME,
+    IDS_FLAGS_ENABLE_REMOTE_ASSISTANCE_DESCRIPTION,
+    kOsCrOS,
+    SINGLE_VALUE_TYPE(extensions::switches::kEnableRemoteAssistance)
+  },
+#endif  // defined(OS_CHROMEOS)
   // NOTE: Adding new command-line switches requires adding corresponding
   // entries to enum "LoginCustomFlags" in histograms.xml. See note in
   // histograms.xml and don't forget to run AboutFlagsHistogramTest unit test.