Update InterceptingResourceHandler tests to use MockResourceLoader.

content/browser/loader/test_resource_handler.cc

Index: content/browser/loader/test_resource_handler.cc
diff --git a/content/browser/loader/test_resource_handler.cc b/content/browser/loader/test_resource_handler.cc
index 86ae04c87e3712c37c0b9037a63e27d9d0ef425e..6cd13a9aa53c076d9f9ac9e0684b9d2e5c9d4ac4 100644
--- a/content/browser/loader/test_resource_handler.cc
+++ b/content/browser/loader/test_resource_handler.cc
@@ -38,7 +38,8 @@ TestResourceHandler::TestResourceHandler(net::URLRequestStatus* request_status,
     : ResourceHandler(nullptr),
       request_status_ptr_(request_status),
       body_ptr_(body),
-      deferred_run_loop_(new base::RunLoop()) {
+      deferred_run_loop_(new base::RunLoop()),
+      weak_ptr_factory_(this) {
   SetBufferSize(2048);
 }
 
@@ -230,4 +231,8 @@ void TestResourceHandler::WaitUntilResponseComplete() {
   response_complete_run_loop_.Run();
 }
 
+base::WeakPtr<TestResourceHandler> TestResourceHandler::GetWeakPtr() {
+  return weak_ptr_factory_.GetWeakPtr();
+}
+
 }  // namespace content