[page_load_metrics] Add a NavigationThrottle for richer abort metrics

components/page_load_metrics/browser/metrics_web_contents_observer_unittest.cc

 // Copyright (c) 2015 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 "components/page_load_metrics/browser/metrics_web_contents_observer.h"
 
 #include <memory>
 #include <vector>
 
 #include "base/macros.h"
 #include "base/memory/ptr_util.h"
 #include "base/process/kill.h"
 #include "base/test/histogram_tester.h"
 #include "base/time/time.h"
+#include "components/page_load_metrics/browser/metrics_navigation_throttle.h"
 #include "components/page_load_metrics/browser/page_load_metrics_observer.h"
 #include "components/page_load_metrics/common/page_load_metrics_messages.h"
 #include "content/public/browser/navigation_handle.h"
 #include "content/public/browser/render_frame_host.h"
 #include "content/public/test/test_renderer_host.h"
 #include "content/public/test/web_contents_tester.h"
 #include "testing/gtest/include/gtest/gtest.h"
 #include "url/gurl.h"
 
 namespace page_load_metrics {
@@ skipping 71 matching lines @@
  private:
   std::vector<PageLoadTiming> updated_timings_;
   std::vector<PageLoadTiming> complete_timings_;
   std::vector<GURL> observed_committed_urls_;
   bool is_prerendering_;
   bool is_ntp_;
 };
 
 }  //  namespace
 
+class AddThrottleWebContentsObserver : public content::WebContentsObserver {
+ public:
+  AddThrottleWebContentsObserver(content::WebContents* contents)
+      : content::WebContentsObserver(contents) {}
+
+  void DidStartNavigation(content::NavigationHandle* handle) override {
+    handle->RegisterThrottleForTesting(
+        MetricsNavigationThrottle::Create(handle));
+  }
+
+ private:
+  DISALLOW_COPY_AND_ASSIGN(AddThrottleWebContentsObserver);
+};
+
 class MetricsWebContentsObserverTest
     : public content::RenderViewHostTestHarness {
  public:
   MetricsWebContentsObserverTest() : num_errors_(0) {}
 
   void SetUp() override {
     RenderViewHostTestHarness::SetUp();
     AttachObserver();
   }
 
   void SimulateTimingUpdate(const PageLoadTiming& timing) {
     SimulateTimingUpdate(timing, web_contents()->GetMainFrame());
   }
 
   void SimulateTimingUpdate(const PageLoadTiming& timing,
                             content::RenderFrameHost* render_frame_host) {
     ASSERT_TRUE(observer_->OnMessageReceived(
         PageLoadMetricsMsg_TimingUpdated(observer_->routing_id(), timing,
                                          PageLoadMetadata()),
         render_frame_host));
   }
 
   void AttachObserver() {
     embedder_interface_ = new TestPageLoadMetricsEmbedderInterface();
-    observer_.reset(new MetricsWebContentsObserver(
-        web_contents(), base::WrapUnique(embedder_interface_)));
+    // Owned by the web_contents. Tests must be careful not to call
+    // SimulateTimingUpdate after they call DeleteContents() without also
+    // calling AttachObserver() again. Otherwise they will use-after-free the
+    // observer_.
+    observer_ = MetricsWebContentsObserver::CreateForWebContents(
+        web_contents(), base::WrapUnique(embedder_interface_));
     observer_->WasShown();
+
+    add_throttling_observer_.reset(
+        new AddThrottleWebContentsObserver(web_contents()));
   }
 
   void CheckErrorEvent(InternalErrorLoadEvent error, int count) {
     histogram_tester_.ExpectBucketCount(internal::kErrorEvents, error, count);
     num_errors_ += count;
   }
 
   void CheckTotalErrorEvents() {
     histogram_tester_.ExpectTotalCount(internal::kErrorEvents, num_errors_);
   }
@@ skipping 18 matching lines @@
     return embedder_interface_->updated_timings().size();
   }
 
   const std::vector<GURL>& observed_committed_urls_from_on_start() const {
     return embedder_interface_->observed_committed_urls_from_on_start();
   }
 
  protected:
   base::HistogramTester histogram_tester_;
   TestPageLoadMetricsEmbedderInterface* embedder_interface_;
-  std::unique_ptr<MetricsWebContentsObserver> observer_;
+  MetricsWebContentsObserver* observer_;
+  std::unique_ptr<AddThrottleWebContentsObserver> add_throttling_observer_;
 
  private:
   int num_errors_;
 
   DISALLOW_COPY_AND_ASSIGN(MetricsWebContentsObserverTest);
 };
 
 TEST_F(MetricsWebContentsObserverTest, SuccessfulMainFrameNavigation) {
   PageLoadTiming timing;
   timing.navigation_start = base::Time::FromDoubleT(1);
@@ skipping 173 matching lines @@
   SimulateTimingUpdate(timing);
   ASSERT_EQ(1, CountUpdatedTimingReported());
   SimulateTimingUpdate(timing2);
   ASSERT_EQ(1, CountUpdatedTimingReported());
 
   CheckErrorEvent(ERR_BAD_TIMING_IPC, 1);
   CheckTotalErrorEvents();
 }
 
 TEST_F(MetricsWebContentsObserverTest, ObservePartialNavigation) {
-  // Delete the observer for this test, add it once the navigation has started.
-  observer_.reset();
+  // Reset the state of the tests, and attach the MetricsWebContentsObserver in
+  // the middle of a navigation. This tests that the class is robust to only
+  // observing some of a navigation.
+  DeleteContents();
+  SetContents(CreateTestWebContents());
+
   PageLoadTiming timing;
   timing.navigation_start = base::Time::FromDoubleT(10);
 
   content::WebContentsTester* web_contents_tester =
       content::WebContentsTester::For(web_contents());
   content::RenderFrameHostTester* rfh_tester =
       content::RenderFrameHostTester::For(main_rfh());
 
   // Start the navigation, then start observing the web contents. This used to
   // crash us. Make sure we bail out and don't log histograms.
@@ skipping 90 matching lines @@
   rfh_tester->SimulateNavigationStop();
 
   web_contents()->Stop();
 
   histogram_tester_.ExpectTotalCount(internal::kAbortChainSizeNoCommit, 1);
   histogram_tester_.ExpectBucketCount(internal::kAbortChainSizeNoCommit, 3,
                                       1);
 }
 
 }  // namespace page_load_metrics