Extensions: Add metrics for Web Request API actions.

extensions/browser/api/web_request/web_request_api_helpers.h

Index: extensions/browser/api/web_request/web_request_api_helpers.h
diff --git a/extensions/browser/api/web_request/web_request_api_helpers.h b/extensions/browser/api/web_request/web_request_api_helpers.h
index b1b9e6cbdb8a601bc2d303141d083f5e459370e4..d6da9813975969eb66c63557f4092c81e5f8d0a0 100644
--- a/extensions/browser/api/web_request/web_request_api_helpers.h
+++ b/extensions/browser/api/web_request/web_request_api_helpers.h
@@ -281,11 +281,14 @@ void MergeCookiesInOnBeforeSendHeadersResponses(
     const net::NetLogWithSource* net_log);
 // Modifies the headers in |request_headers| according to |deltas|. Conflicts
 // are tried to be resolved.
+// Stores in |request_headers_modified| whether the request headers were
+// modified.
 void MergeOnBeforeSendHeadersResponses(
     const EventResponseDeltas& deltas,
     net::HttpRequestHeaders* request_headers,
     extensions::WarningSet* conflicting_extensions,
-    const net::NetLogWithSource* net_log);
+    const net::NetLogWithSource* net_log,
+    bool* request_headers_modified);
 // Modifies the "Set-Cookie" headers in |override_response_headers| according to
 // |deltas.response_cookie_modifications|. If |override_response_headers| is
 // NULL, a copy of |original_response_headers| is created. Conflicts are
@@ -302,6 +305,8 @@ void MergeCookiesInOnHeadersReceivedResponses(
 // Extension-initiated redirects are written to |override_response_headers|
 // (to request redirection) and |*allowed_unsafe_redirect_url| (to make sure
 // that the request is not cancelled with net::ERR_UNSAFE_REDIRECT).
+// Stores in |response_headers_modified| whether the response headers were
+// modified.
 void MergeOnHeadersReceivedResponses(
     const GURL& url,
     const EventResponseDeltas& deltas,
@@ -309,7 +314,8 @@ void MergeOnHeadersReceivedResponses(
     scoped_refptr<net::HttpResponseHeaders>* override_response_headers,
     GURL* allowed_unsafe_redirect_url,
     extensions::WarningSet* conflicting_extensions,
-    const net::NetLogWithSource* net_log);
+    const net::NetLogWithSource* net_log,
+    bool* response_headers_modified);
 // Merge the responses of blocked onAuthRequired handlers. The first
 // registered listener that supplies authentication credentials in a response,
 // if any, will have its authentication credentials used. |request| must be