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..3c013ab4b3226f9241530cc54a981515dee46aa0 100644
--- a/chrome/browser/predictors/resource_prefetch_predictor_browsertest.cc
+++ b/chrome/browser/predictors/resource_prefetch_predictor_browsertest.cc
@@ -61,12 +61,31 @@ class InitializationObserver : public TestObserver {
   DISALLOW_COPY_AND_ASSIGN(InitializationObserver);
 };
 
+using PageRequestSummary = ResourcePrefetchPredictor::PageRequestSummary;
+using URLRequestSummary = ResourcePrefetchPredictor::URLRequestSummary;
+
+std::vector<URLRequestSummary> GetUniqueSubresources(
+    const PageRequestSummary& summary) {
+  std::vector<URLRequestSummary> subresources(

[Benoit L, 2016/11/28 14:58:04]

nit: why not just a copy?

[alexilin, 2016/11/28 15:12:15]

Done.

+      summary.subresource_requests.begin(), summary.subresource_requests.end());
+  std::sort(subresources.begin(), subresources.end(),

[Benoit L, 2016/11/28 14:58:04]

Do you need stable_sort here?

[alexilin, 2016/11/28 15:12:15]

Thanks! Indeed we need first occurrences of each subresource.
Done.

+            [](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,
@@ -83,7 +102,7 @@ class ResourcePrefetchPredictorTestObserver : public TestObserver {
     EXPECT_EQ(summary.main_frame_url, summary_.main_frame_url);
     EXPECT_EQ(summary.initial_url, summary_.initial_url);
     EXPECT_THAT(

[Benoit L, 2016/11/28 14:58:04]

Can you add a comment to explain that we have duplicate resources, and that only
care about the (first?) occurrence of each?

[alexilin, 2016/11/28 15:12:15]

Done.

-        summary.subresource_requests,
+        GetUniqueSubresources(summary),
         testing::UnorderedElementsAreArray(summary_.subresource_requests));
     run_loop_.Quit();
   }
@@ -100,7 +119,6 @@ class ResourcePrefetchPredictorTestObserver : public TestObserver {
 
 class ResourcePrefetchPredictorBrowserTest : public InProcessBrowserTest {
  protected:
-  using URLRequestSummary = ResourcePrefetchPredictor::URLRequestSummary;
 
   void SetUpCommandLine(base::CommandLine* command_line) override {
     command_line->AppendSwitchASCII(