Keep track of how many documents had a resource intercepted by foreign fetch.

third_party/WebKit/public/platform/WebURLResponse.h

Index: third_party/WebKit/public/platform/WebURLResponse.h
diff --git a/third_party/WebKit/public/platform/WebURLResponse.h b/third_party/WebKit/public/platform/WebURLResponse.h
index d44a28e1bc9605f3a68ff48eb1351f226567b1a8..ca7f9960eb6e6a243fc5b7e5dbf6b497a5b13d00 100644
--- a/third_party/WebKit/public/platform/WebURLResponse.h
+++ b/third_party/WebKit/public/platform/WebURLResponse.h
@@ -231,6 +231,10 @@ public:
     BLINK_PLATFORM_EXPORT bool wasFetchedViaServiceWorker() const;
     BLINK_PLATFORM_EXPORT void setWasFetchedViaServiceWorker(bool);
 
+    // Flag whether this request was loaded using a foreign fetch service worker.
+    BLINK_PLATFORM_EXPORT bool wasFetchedViaForeignFetch() const;
+    BLINK_PLATFORM_EXPORT void setWasFetchedViaForeignFetch(bool);
+
     // Flag whether the fallback request with skip service worker flag was
     // required.
     BLINK_PLATFORM_EXPORT bool wasFallbackRequiredByServiceWorker() const;