predictors: Ignore repeating subresources while checking.

chrome/browser/predictors/resource_prefetch_predictor_browsertest.cc

Index: chrome/browser/predictors/resource_prefetch_predictor_browsertest.cc
diff --git a/chrome/browser/predictors/resource_prefetch_predictor_browsertest.cc b/chrome/browser/predictors/resource_prefetch_predictor_browsertest.cc
index 4981a2a2fffb486d5a090044142b217c01d34091..48073a12a0f3cf0b97da597337838e48b8bb0ec9 100644
--- a/chrome/browser/predictors/resource_prefetch_predictor_browsertest.cc
+++ b/chrome/browser/predictors/resource_prefetch_predictor_browsertest.cc
@@ -61,12 +61,30 @@ class InitializationObserver : public TestObserver {
   DISALLOW_COPY_AND_ASSIGN(InitializationObserver);
 };
 
+using PageRequestSummary = ResourcePrefetchPredictor::PageRequestSummary;
+using URLRequestSummary = ResourcePrefetchPredictor::URLRequestSummary;
+
+std::vector<URLRequestSummary> GetUniqueSubresources(

[pasko, 2016/11/28 15:41:28]

nit: anonymous namespace for everything between
kImagePath..GetUniqueSubresources

The predictors namespace is not big, but it is good to be explicit about these
things not being declared outside this file.

[alexilin, 2016/11/29 10:32:00]

Done.

+    const PageRequestSummary& summary) {
+  std::vector<URLRequestSummary> subresources(summary.subresource_requests);
+  std::stable_sort(subresources.begin(), subresources.end(),
+                   [](const URLRequestSummary& x, const URLRequestSummary& y) {
+                     return x.resource_url < y.resource_url;
+                   });
+  subresources.erase(
+      std::unique(subresources.begin(), subresources.end(),
+                  [](const URLRequestSummary& x, const URLRequestSummary& y) {
+                    return x.resource_url == y.resource_url;
+                  }),
+      subresources.end());
+  return subresources;
+}
+
 // 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 {
  public:
-  using PageRequestSummary = ResourcePrefetchPredictor::PageRequestSummary;
 
   explicit ResourcePrefetchPredictorTestObserver(
       ResourcePrefetchPredictor* predictor,
@@ -82,9 +100,11 @@ class ResourcePrefetchPredictorTestObserver : public TestObserver {
     EXPECT_EQ(url_visit_count, url_visit_count_);
     EXPECT_EQ(summary.main_frame_url, summary_.main_frame_url);
     EXPECT_EQ(summary.initial_url, summary_.initial_url);
-    EXPECT_THAT(
-        summary.subresource_requests,
-        testing::UnorderedElementsAreArray(summary_.subresource_requests));
+    // Duplicate resources can be observed in a single navigation but
+    // ResourcePrefetchPredictor only cares about the first occurrence of each.
+    vector<URLRequestSummary> subresources = GetUniqueSubresources(summary);
+    EXPECT_THAT(subresources, testing::UnorderedElementsAreArray(
+                                  summary_.subresource_requests));
     run_loop_.Quit();
   }
 
@@ -100,7 +120,6 @@ class ResourcePrefetchPredictorTestObserver : public TestObserver {
 
 class ResourcePrefetchPredictorBrowserTest : public InProcessBrowserTest {
  protected:
-  using URLRequestSummary = ResourcePrefetchPredictor::URLRequestSummary;
 
   void SetUpCommandLine(base::CommandLine* command_line) override {
     command_line->AppendSwitchASCII(