Make VibrationMessageFilter available to other platforms.

content/public/browser/content_browser_client.cc

Index: content/public/browser/content_browser_client.cc
diff --git a/content/public/browser/content_browser_client.cc b/content/public/browser/content_browser_client.cc
index 136a0126e4d1e2311e2c982bbc9c1d1b8515f9a2..b0abc4fa9755a8c03c251253d3b9dbbdd225bec0 100644
--- a/content/public/browser/content_browser_client.cc
+++ b/content/public/browser/content_browser_client.cc
@@ -288,6 +288,10 @@ LocationProvider* ContentBrowserClient::OverrideSystemLocationProvider() {
   return NULL;
 }
 
+VibrationProvider* ContentBrowserClient::OverrideVibrationProvider() {
+  return NULL;
+}
+
 #if defined(OS_WIN)
 const wchar_t* ContentBrowserClient::GetResourceDllName() {
   return NULL;