PlzNavigate: Eliminate test_runner bailing out of layout tests too early

components/test_runner/test_runner.h

Index: components/test_runner/test_runner.h
diff --git a/components/test_runner/test_runner.h b/components/test_runner/test_runner.h
index d9e1a1ca68f3e8bc5039f37644a854a61efe9bac..c169a88e5539e554653df56230a4f79d1615708f 100644
--- a/components/test_runner/test_runner.h
+++ b/components/test_runner/test_runner.h
@@ -99,6 +99,8 @@ class TestRunner : public WebTestRunner {
   void SetFocus(blink::WebView* web_view, bool focus) override;
 
   // Methods used by WebViewTestClient and WebFrameTestClient.
+  void OnNavigationBegin() { is_navigating_ = true; }
+  void OnNavigationEnd() { is_navigating_ = false; }
   void OnAnimationScheduled(blink::WebWidget* widget);
   void OnAnimationBegun(blink::WebWidget* widget);
   std::string GetAcceptLanguages() const;
@@ -614,6 +616,11 @@ class TestRunner : public WebTestRunner {
 
   bool use_mock_theme_;
 
+  // This is true in the period between the start of a navigation and when that
+  // navigation commits or fails. Note that when browser-side navigation is
+  // enabled there is an arbitrary gap between these two events.

[clamy, 2016/07/19 13:50:35]

Wouldn't that be the case in the current architecture as well, since we need the
browser to fetch the resource in both cases?

[blundell, 2016/07/21 10:02:18]

Yes, good point. The PlzNavigate-specific gap is between navigation being
started and WebFrameClient::didStartProvisionalLoad(frame*) being called. It's
the latter callback that causes TestRunner's tryToSetTopLoadingFrame(frame*) to
be invoked, which TestRunner relies on for detecting that a load is active.

Updated the comment to be precise.

+  bool is_navigating_;
+
   std::unique_ptr<MockCredentialManagerClient> credential_manager_client_;
   std::unique_ptr<MockScreenOrientationClient> mock_screen_orientation_client_;
   std::unique_ptr<MockWebSpeechRecognizer> speech_recognizer_;