Extensions: Add metrics for Web Request API actions.

extensions/browser/api/web_request/web_request_api.cc

 // Copyright (c) 2012 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "extensions/browser/api/web_request/web_request_api.h"
 
 #include <stddef.h>
 
 #include <algorithm>
 #include <memory>
@@ skipping 69 matching lines @@
 namespace helpers = extension_web_request_api_helpers;
 namespace keys = extension_web_request_api_constants;
 
 namespace extensions {
 
 namespace declarative_keys = declarative_webrequest_constants;
 namespace web_request = api::web_request;
 
 namespace {
 
+// Describes the action taken by the Web Request API for a given stage of a web
+// request.
+// These values are written to logs.  New enum values can be added, but existing
+// enum values must never be renumbered or deleted and reused.
+enum RequestAction {
+  CANCEL = 0,
+  REDIRECT = 1,
+  MODIFY_REQUEST_HEADERS = 2,
+  MODIFY_RESPONSE_HEADERS = 3,
+  SET_AUTH_CREDENTIALS = 4,
+  MAX
+};
+
 const char kWebRequestEventPrefix[] = "webRequest.";
 
 // List of all the webRequest events.
 const char* const kWebRequestEvents[] = {
   keys::kOnBeforeRedirectEvent,
   web_request::OnBeforeRequest::kEventName,
   keys::kOnBeforeSendHeadersEvent,
   keys::kOnCompletedEvent,
   web_request::OnErrorOccurred::kEventName,
   keys::kOnSendHeadersEvent,
@@ skipping 23 matching lines @@
       return keys::kOnResponseStarted;
     case ExtensionWebRequestEventRouter::kOnErrorOccurred:
       return keys::kOnErrorOccurred;
     case ExtensionWebRequestEventRouter::kOnCompleted:
       return keys::kOnCompleted;
   }
   NOTREACHED();
   return "Not reached";
 }
 
+void LogRequestAction(RequestAction action) {
+  DCHECK_NE(RequestAction::MAX, action);
+  UMA_HISTOGRAM_ENUMERATION("Extensions.WebRequestAction", action,
+                            RequestAction::MAX);
+}
+
 bool IsWebRequestEvent(const std::string& event_name) {
   std::string web_request_event_name(event_name);
   if (base::StartsWith(web_request_event_name,
                        webview::kWebViewEventPrefix,
                        base::CompareCase::SENSITIVE)) {
     web_request_event_name.replace(
         0, strlen(webview::kWebViewEventPrefix), kWebRequestEventPrefix);
   }
   auto* const* web_request_events_end =
       kWebRequestEvents + arraysize(kWebRequestEvents);
@@ skipping 1650 matching lines @@
     uint64_t request_id,
     ExtensionNavigationUIData* navigation_ui_data,
     bool call_callback) {
   BlockedRequest& blocked_request = blocked_requests_[request_id];
   CHECK_EQ(0, blocked_request.num_handlers_blocking);
   helpers::EventResponseDeltas& deltas = blocked_request.response_deltas;
   base::TimeDelta block_time =
       base::Time::Now() - blocked_request.blocking_time;
   request_time_tracker_->IncrementTotalBlockTime(request_id, block_time);
 
+  bool request_headers_modified = false;
+  bool response_headers_modified = false;
   bool credentials_set = false;
 
   deltas.sort(&helpers::InDecreasingExtensionInstallationTimeOrder);
 
   bool canceled = false;
   helpers::MergeCancelOfResponses(blocked_request.response_deltas, &canceled,
                                   blocked_request.net_log);
 
   WarningSet warnings;
   if (blocked_request.event == kOnBeforeRequest) {
     CHECK(!blocked_request.callback.is_null());
     helpers::MergeOnBeforeRequestResponses(
         blocked_request.request->url(), blocked_request.response_deltas,
         blocked_request.new_url, &warnings, blocked_request.net_log);
   } else if (blocked_request.event == kOnBeforeSendHeaders) {
     CHECK(!blocked_request.callback.is_null());
     helpers::MergeOnBeforeSendHeadersResponses(
-        blocked_request.response_deltas,
-        blocked_request.request_headers,
-        &warnings,
-        blocked_request.net_log);
+        blocked_request.response_deltas, blocked_request.request_headers,
+        &warnings, blocked_request.net_log, &request_headers_modified);
   } else if (blocked_request.event == kOnHeadersReceived) {
     CHECK(!blocked_request.callback.is_null());
     helpers::MergeOnHeadersReceivedResponses(
         blocked_request.request->url(), blocked_request.response_deltas,
         blocked_request.original_response_headers.get(),
         blocked_request.override_response_headers, blocked_request.new_url,
-        &warnings, blocked_request.net_log);
+        &warnings, blocked_request.net_log, &response_headers_modified);
   } else if (blocked_request.event == kOnAuthRequired) {
     CHECK(blocked_request.callback.is_null());
     CHECK(!blocked_request.auth_callback.is_null());
     credentials_set = helpers::MergeOnAuthRequiredResponses(
        blocked_request.response_deltas,
        blocked_request.auth_credentials,
        &warnings,
        blocked_request.net_log);
   } else {
     NOTREACHED();
   }
 
   SendMessages(browser_context, blocked_request, navigation_ui_data);
 
   if (!warnings.empty()) {
     BrowserThread::PostTask(
         BrowserThread::UI,
         FROM_HERE,
         base::Bind(&WarningService::NotifyWarningsOnUI,
                    browser_context, warnings));
   }
 
-  if (canceled) {
+  const bool redirected =
+      blocked_request.new_url && !blocked_request.new_url->is_empty();
+
+  if (canceled)
     request_time_tracker_->SetRequestCanceled(request_id);
-  } else if (blocked_request.new_url &&
-             !blocked_request.new_url->is_empty()) {
+  else if (redirected)
     request_time_tracker_->SetRequestRedirected(request_id);
-  }
+
+  // Log UMA metrics. Note: We are not necessarily concerned with the final
+  // action taken. Instead we are interested in how frequently the different
+  // actions are used by extensions. Hence multiple actions may be logged for a
+  // single delta execution.
+  if (canceled)
+    LogRequestAction(RequestAction::CANCEL);
+  if (redirected)
+    LogRequestAction(RequestAction::REDIRECT);
+  if (request_headers_modified)
+    LogRequestAction(RequestAction::MODIFY_REQUEST_HEADERS);
+  if (response_headers_modified)
+    LogRequestAction(RequestAction::MODIFY_RESPONSE_HEADERS);
+  if (credentials_set)
+    LogRequestAction(RequestAction::SET_AUTH_CREDENTIALS);
 
   // This triggers onErrorOccurred if canceled is true.
   int rv = canceled ? net::ERR_BLOCKED_BY_CLIENT : net::OK;
 
   if (!blocked_request.callback.is_null()) {
     net::CompletionCallback callback = blocked_request.callback;
     // Ensure that request is removed before callback because the callback
     // might trigger the next event.
     blocked_requests_.erase(request_id);
     if (call_callback)
@@ skipping 521 matching lines @@
   // Since EventListeners are segmented by browser_context, check that
   // last, as it is exceedingly unlikely to be different.
   return extension_id == that.extension_id &&
          sub_event_name == that.sub_event_name &&
          web_view_instance_id == that.web_view_instance_id &&
          embedder_process_id == that.embedder_process_id &&
          browser_context == that.browser_context;
 }
 
 }  // namespace extensions