Track where WebContents are created in order to better understand issue.

android_webview/native/aw_contents.cc

Index: android_webview/native/aw_contents.cc
diff --git a/android_webview/native/aw_contents.cc b/android_webview/native/aw_contents.cc
index 4a829faba54b118a22fb0e754abd9afe931e9574..3eab578064812c7639b30353df84553c0b96b7e6 100644
--- a/android_webview/native/aw_contents.cc
+++ b/android_webview/native/aw_contents.cc
@@ -63,6 +63,7 @@
 #include "content/public/browser/render_process_host.h"
 #include "content/public/browser/render_view_host.h"
 #include "content/public/browser/web_contents.h"
+#include "content/public/browser/web_contents_source.h"
 #include "content/public/common/message_port_types.h"
 #include "content/public/common/renderer_preferences.h"
 #include "content/public/common/ssl_status.h"
@@ -320,6 +321,8 @@ static jlong Init(JNIEnv* env,
   // than hard-code the default instance lookup here.
   scoped_ptr<WebContents> web_contents(content::WebContents::Create(
       content::WebContents::CreateParams(AwBrowserContext::GetDefault())));
+  WebContentsSource::CreateForWebContentsAndLocation(web_contents.get(),
+                                                     FROM_HERE);
   // Return an 'uninitialized' instance; most work is deferred until the
   // subsequent SetJavaPeers() call.
   return reinterpret_cast<intptr_t>(new AwContents(web_contents.Pass()));