desktop-pwas: Record delta between opening an app window and last navigation

If the time difference is small, then we probably opened an app window
in response to a client side redirect and left the tab opened. This
will let us know how common this problem is.

Bug: 785661
Change-Id: Icc5a015cd5c0ae9fda5ad457ad564ead4b812332
Reviewed-on: https://chromium-review.googlesource.com/798951
Commit-Queue: Giovanni Ortuño Urquidi <ortuno@chromium.org>
Reviewed-by: Alexei Svitkine <asvitkine@chromium.org>
Reviewed-by: Matt Giuca <mgiuca@chromium.org>
Reviewed-by: Ben Wells <benwells@chromium.org>
Cr-Commit-Position: refs/heads/master@{#522307}

chrome/browser/extensions/bookmark_app_navigation_throttle.cc

@@ -23,6 +23,7 @@
 #include "chrome/common/extensions/api/url_handlers/url_handlers_parser.h"
 #include "content/public/browser/browser_context.h"
 #include "content/public/browser/browser_thread.h"
+#include "content/public/browser/navigation_entry.h"
 #include "content/public/browser/navigation_handle.h"
 #include "content/public/browser/render_frame_host.h"
 #include "content/public/browser/web_contents.h"
@@ -349,6 +350,19 @@ BookmarkAppNavigationThrottle::ProcessNavigation(bool is_redirect) {
       return content::NavigationThrottle::CANCEL_AND_IGNORE;
     }
 
+    content::NavigationEntry* last_entry = navigation_handle()
+                                               ->GetWebContents()
+                                               ->GetController()
+                                               .GetLastCommittedEntry();
+    // We are about to open a new app window context. Record the time since the
+    // last navigation in this context. (If it is very small, this context
+    // probably redirected immediately, which is a bad user experience.)
+    if (last_entry && !last_entry->GetTimestamp().is_null()) {
+      UMA_HISTOGRAM_MEDIUM_TIMES(
+          "Extensions.BookmarkApp.OpenAppDeltaSinceLastNavigation",
+          base::Time::Now() - last_entry->GetTimestamp());
+    }
+
     content::NavigationThrottle::ThrottleCheckResult result =
         OpenInAppWindowAndCloseTabIfNecessary(target_app);
 

tools/metrics/histograms/histograms.xml

@@ -22435,6 +22435,17 @@ http://cs/file:chrome/histograms.xml - but prefer this file for new entries.
   </summary>
 </histogram>
 
+<histogram name="Extensions.BookmarkApp.TimeBetweenOpenAppAndLastNavigation"
+    units="ms">
+  <owner>mgiuca@chromium.org</owner>
+  <owner>ortuno@chromium.org</owner>
+  <summary>
+    The time between the last navigation in the context and us opening a new app
+    window in response to a new navigation. If it is very small, the context
+    probably redirected immediately, which is a bad user experience.
+  </summary>
+</histogram>
+
 <histogram name="Extensions.BookmarkAppLaunchContainer"
     enum="AppLaunchContainer">
   <owner>benwells@chromium.org</owner>