predictors: Fuzzy comparison of request priority for images.

chrome/browser/predictors/resource_prefetch_predictor_browsertest.cc

 // Copyright 2016 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 "base/command_line.h"
 #include "chrome/browser/predictors/resource_prefetch_predictor.h"
 #include "chrome/browser/predictors/resource_prefetch_predictor_factory.h"
 #include "chrome/browser/predictors/resource_prefetch_predictor_test_util.h"
 #include "chrome/browser/profiles/profile.h"
 #include "chrome/browser/ui/browser.h"
@@ skipping 94 matching lines @@
 }
 
 // Fill a NavigationID with "empty" data that does not trigger
 // the is_valid DCHECK(). Allows comparing.
 void SetValidNavigationID(NavigationID* navigation_id) {
   navigation_id->render_process_id = 0;
   navigation_id->render_frame_id = 0;
   navigation_id->main_frame_url = GURL("http://127.0.0.1");
 }
 
+void ModifySubresourceForComparison(URLRequestSummary* subresource,
+                                    bool match_navigation_id) {
+  if (!match_navigation_id)
+    SetValidNavigationID(&subresource->navigation_id);
+  if (subresource->resource_type == content::RESOURCE_TYPE_IMAGE &&
+      subresource->priority == net::LOWEST) {
+    // Fuzzy comparison for images because an image priority can be
+    // boosted during layout via
+    // ResourceFetcher::updateAllImageResourcePriorities().
+    subresource->priority = net::MEDIUM;
+  }
+}
+
 // Does a custom comparison of subresources of URLRequestSummary
 // and fail the test if the expectation is not met.
 void CompareSubresources(std::vector<URLRequestSummary> actual_subresources,
                          std::vector<URLRequestSummary> expected_subresources,
                          bool match_navigation_id) {
   // Duplicate resources can be observed in a single navigation but
   // ResourcePrefetchPredictor only cares about the first occurrence of each.
   RemoveDuplicateSubresources(&actual_subresources);
 
-  if (!match_navigation_id) {
-    for (auto& subresource : actual_subresources)
-      SetValidNavigationID(&subresource.navigation_id);
-    for (auto& subresource : expected_subresources)
-      SetValidNavigationID(&subresource.navigation_id);
-  }
+  for (auto& subresource : actual_subresources)
+    ModifySubresourceForComparison(&subresource, match_navigation_id);
+  for (auto& subresource : expected_subresources)
+    ModifySubresourceForComparison(&subresource, match_navigation_id);
+
   EXPECT_THAT(actual_subresources,
               testing::UnorderedElementsAreArray(expected_subresources));
 }
 
 }  // namespace
 
 // Helper class to track and allow waiting for ResourcePrefetchPredictor events.
 // These events are also used to verify that ResourcePrefetchPredictor works as
 // expected.
 class ResourcePrefetchPredictorTestObserver : public TestObserver {
@@ skipping 371 matching lines @@
   AddResource(GetURL(kStylePath2), content::RESOURCE_TYPE_STYLESHEET,
               net::HIGHEST);
   AddResource(GetURL(kScriptPath2), content::RESOURCE_TYPE_SCRIPT, net::MEDIUM);
   // Included from <iframe src="html_subresources.html"> and not recored.
   AddUnrecordedResources({GetURL(kImagePath), GetURL(kStylePath),
                           GetURL(kScriptPath), GetURL(kFontPath)});
   NavigateToURLAndCheckSubresources(GetURL(kHtmlIframePath));
 }
 
 }  // namespace predictors