[page_load_metrics] Add a NavigationThrottle for richer abort metrics

content/public/test/browser_test_utils.h

Index: content/public/test/browser_test_utils.h
diff --git a/content/public/test/browser_test_utils.h b/content/public/test/browser_test_utils.h
index 52f48f18fd7330fcf6c6a9f155c2288064e05d9c..7ffd2a3204cc4ffa1a2b6012ff9643b8ccd1b93f 100644
--- a/content/public/test/browser_test_utils.h
+++ b/content/public/test/browser_test_utils.h
@@ -61,6 +61,7 @@ namespace content {
 
 class BrowserContext;
 class MessageLoopRunner;
+class NavigationHandle;
 class RenderViewHost;
 class RenderWidgetHost;
 class WebContents;
@@ -574,6 +575,61 @@ class BrowserTestClipboardScope {
   DISALLOW_COPY_AND_ASSIGN(BrowserTestClipboardScope);
 };
 
+// This class can be used to pause and resume navigations, based on a URL
+// match. Note that it only keeps track of one navigation at a time.
+// Navigations are paused automatically before hitting the network, and are
+// resumed automatically if a Wait method is called for a future event.
+// Note: This class is one time use only! After it successfully tracks a
+// navigation it will ignore all subsequent navigations. Explicitly create
+// mutliple of these managers if you want to pause multiple navigations.

[nasko, 2016/08/01 15:29:23]

nit: "multiple instances of this class if you ..."

[Charlie Harrison, 2016/08/01 17:42:19]

Done.

+class TestNavigationManager : public WebContentsObserver {
+ public:
+  // Monitors notifications within the given frame tree node. Use the other

[nasko, 2016/08/01 15:29:23]

FrameTreeNode is mostly internal concept to content/. We have had to expose it
in a couple of places, but this one doesn't look necessary. Why not drop this
one, since the next constructor should be good enough?

I think an content/ internal version using the FTN will be nice to have.

[Charlie Harrison, 2016/08/01 17:42:19]

So, Camille wanted this functionality as a prereq for exposing class this to the
public API. What if we took a RenderFrameHost as argument, and internally used
its FTN? The exposed API could say something like:
"Intercepts navigations in the frame hosted by the given RFH". How does that
sound to you?

[nasko, 2016/08/01 23:38:11]

We don't have anyone outside of content/ using this constructor, do we? If not,
we should not be exposing it.

[Charlie Harrison, 2016/08/02 13:09:15]

Fair point.  I've removed the method and added a subclass that does this
filtering private to content.

+  // constructor if the manager should monitor all frames, which is equivalent
+  // to passing kFrameTreeNodeInvalidId for |frame_tree_node_id|.
+  TestNavigationManager(int frame_tree_node_id,
+                        WebContents* web_contents,
+                        const GURL& url);
+
+  // Monitors any frame in WebContents.
+  TestNavigationManager(WebContents* web_contents, const GURL& url);
+
+  ~TestNavigationManager() override;
+
+  // Waits until the navigation request is ready to be sent to the network
+  // stack. Returns false if the request was aborted before starting.
+  WARN_UNUSED_RESULT bool WaitForWillStartRequest();
+
+  // Waits until the navigation has been finished. Will automatically resume
+  // navigations paused before this point.
+  void WaitForNavigationFinished();
+
+ private:
+  // WebContentsObserver:
+  void DidStartNavigation(NavigationHandle* handle) override;
+  void DidFinishNavigation(NavigationHandle* handle) override;
+
+  // Called when the NavigationThrottle pauses the navigation in
+  // WillStartRequest.
+  void OnWillStartRequest();
+
+  // Resumes the navigation.
+  void ResumeNavigation();
+
+  // If this member is not |kFrameTreeNodeInvalidId|, notifications are filtered
+  // so only this frame is monitored.
+  int filtering_frame_tree_node_id_;
+
+  const GURL url_;
+  bool navigation_paused_;
+  NavigationHandle* handle_;
+  bool handled_navigation_;
+  scoped_refptr<MessageLoopRunner> will_start_loop_runner_;
+  scoped_refptr<MessageLoopRunner> did_finish_loop_runner_;
+
+  base::WeakPtrFactory<TestNavigationManager> weak_factory_;
+};
+
 }  // namespace content
 
 #endif  // CONTENT_PUBLIC_TEST_BROWSER_TEST_UTILS_H_