Implement CSP check for manifest fetching

Source/core/testing/URLTestHelpers.cpp

Index: Source/core/testing/URLTestHelpers.cpp
diff --git a/Source/core/testing/URLTestHelpers.cpp b/Source/core/testing/URLTestHelpers.cpp
index 1a0f261d8b1eb85092806f31d44bfd7c6dfd4a4a..f7ac96a02444f02fb38f7e171a53da0f342a6599 100644
--- a/Source/core/testing/URLTestHelpers.cpp
+++ b/Source/core/testing/URLTestHelpers.cpp
@@ -57,6 +57,11 @@ void registerMockedURLLoad(const WebURL& fullURL, const WebString& fileName, con
     response.setMIMEType(mimeType);
     response.setHTTPStatusCode(200);
 
+    registerMockedURLLoadWithCustomResponse(fullURL, fileName, relativeBaseDirectory, response);
+}
+
+void registerMockedURLLoadWithCustomResponse(const WebURL& fullURL, const WebString& fileName, const WebString& relativeBaseDirectory, WebURLResponse response)
+{
     // Physical file path for the mock = <webkitRootDir> + relativeBaseDirectory + fileName.
     std::string filePath = std::string(Platform::current()->unitTestSupport()->webKitRootDir().utf8().data());
     filePath.append("/Source/web/tests/data/");