[Android WebView] Call shouldInterceptRequest on a background thread

android_webview/browser/aw_request_interceptor.h

Index: android_webview/browser/aw_request_interceptor.h
diff --git a/android_webview/browser/aw_request_interceptor.h b/android_webview/browser/aw_request_interceptor.h
index a3c54b3a26dd692988c9fb1d412c7f033134cbd6..57dd7d82c643d7fa4d4be1aa497f6e7cf01e0fa3 100644
--- a/android_webview/browser/aw_request_interceptor.h
+++ b/android_webview/browser/aw_request_interceptor.h
@@ -8,19 +8,14 @@
 #include "base/memory/scoped_ptr.h"
 #include "net/url_request/url_request_interceptor.h"
 
-class GURL;
-
 namespace net {
 class URLRequest;
-class URLRequestContextGetter;
 class URLRequestJob;
 class NetworkDelegate;
 }
 
 namespace android_webview {
 
-class AwWebResourceResponse;
-
 // This class allows the Java-side embedder to substitute the default
 // URLRequest of a given request for an alternative job that will read data
 // from a Java stream.
@@ -35,9 +30,6 @@ class AwRequestInterceptor : public net::URLRequestInterceptor {
       net::NetworkDelegate* network_delegate) const override;
 
  private:
-  scoped_ptr<AwWebResourceResponse> QueryForAwWebResourceResponse(
-      net::URLRequest* request) const;
-
   DISALLOW_COPY_AND_ASSIGN(AwRequestInterceptor);
 };