Manually load the original page when ReloadType::ORIGINAL_REQUEST_URL

This is a manual workaround so that HTTPS Server Previews can be team
fooded in 71 and will need to be merged back into the M71 branch.

This checks if the user is on a preview page and is reloading via
clicking the "load original" UI and if so, loads the orignal page.

Bug: 864187
Change-Id: I2c8ed4edba98f30f398675c38d7f89d3848a0212
Reviewed-on: https://chromium-review.googlesource.com/c/1280853Reviewed-by: Tarun Bansal <tbansal@chromium.org>
Commit-Queue: Robert Ogden <robertogden@chromium.org>
Cr-Commit-Position: refs/heads/master@{#599699}

chrome/browser/previews/previews_lite_page_browsertest.cc

@@ -680,6 +680,32 @@ IN_PROC_BROWSER_TEST_F(PreviewsLitePageServerBrowserTest,
   }
 }
 
+// Previews InfoBar (which these tests trigger) does not work on Mac.
+// See https://crbug.com/782322 for detail.
+// Also occasional flakes on win7 (https://crbug.com/789542).
+#if defined(OS_ANDROID) || defined(OS_LINUX)
+#define MAYBE_LitePagePreviewsReload LitePagePreviewsReload
+#else
+#define MAYBE_LitePagePreviewsReload DISABLED_LitePagePreviewsReload
+#endif
+IN_PROC_BROWSER_TEST_F(PreviewsLitePageServerBrowserTest,
+                       MAYBE_LitePagePreviewsReload) {
+  ui_test_utils::NavigateToURL(browser(), HttpsLitePageURL(kSuccess));
+  VerifyPreviewLoaded();
+
+  GetWebContents()->GetController().Reload(content::ReloadType::NORMAL, false);
+  VerifyPreviewLoaded();
+
+  base::HistogramTester histogram_tester;
+  GetWebContents()->GetController().Reload(
+      content::ReloadType::ORIGINAL_REQUEST_URL, false);
+  VerifyPreviewNotLoaded();
+  histogram_tester.ExpectBucketCount(
+      "Previews.ServerLitePage.IneligibleReasons",
+      PreviewsLitePageNavigationThrottle::IneligibleReason::kLoadOriginalReload,
+      1);
+}
+
 // Previews InfoBar (which these tests trigger) does not work on Mac.
 // See https://crbug.com/782322 for detail.
 // Also occasional flakes on win7 (https://crbug.com/789542).
@@ -893,10 +919,6 @@ IN_PROC_BROWSER_TEST_F(PreviewsLitePageServerBrowserTest,
   // Navigate back again.
   GetWebContents()->GetController().GoBack();
   VerifyPreviewLoaded();
-
-  // Reload.
-  GetWebContents()->GetController().Reload(content::ReloadType::NORMAL, false);
-  VerifyPreviewLoaded();
 }
 
 class PreviewsLitePageServerTimeoutBrowserTest

chrome/browser/previews/previews_lite_page_navigation_throttle.cc

@@ -399,6 +399,21 @@ PreviewsLitePageNavigationThrottle::TriggerPreview() const {
 
 content::NavigationThrottle::ThrottleCheckResult
 PreviewsLitePageNavigationThrottle::MaybeNavigateToPreview() const {
+  // First check if the user is attempting to load the original page on a
+  // preview.
+  std::string original_url;
+  if (navigation_handle()->GetReloadType() ==
+          content::ReloadType::ORIGINAL_REQUEST_URL &&
+      GetOriginalURL(navigation_handle()->GetURL(), &original_url)) {
+    LoadAndBypass(navigation_handle()->GetWebContents(), manager_,
+                  MakeOpenURLParams(navigation_handle(), GURL(original_url),
+                                    std::string()),
+                  true);
+    UMA_HISTOGRAM_ENUMERATION("Previews.ServerLitePage.IneligibleReasons",
+                              IneligibleReason::kLoadOriginalReload);
+    return content::NavigationThrottle::CANCEL;
+  }
+
   const bool trigger =
       IsEligibleForPreview() &&
       !manager_->CheckSingleBypass(navigation_handle()->GetURL().spec());

chrome/browser/previews/previews_lite_page_navigation_throttle.h

@@ -56,7 +56,8 @@ class PreviewsLitePageNavigationThrottle : public content::NavigationThrottle {
     kServerUnavailable = 3,
     kInfoBarNotSeen = 4,
     kNetworkNotSlow = 5,
-    kMaxValue = kNetworkNotSlow,
+    kLoadOriginalReload = 6,
+    kMaxValue = kLoadOriginalReload,
   };
 
   // The response type from the previews server. This enum must

tools/metrics/histograms/enums.xml

@@ -40882,6 +40882,7 @@ Called by update_net_trust_anchors.py.-->
   <int value="3" label="Server Unavailable"/>
   <int value="4" label="Infobar hasn't been seen by the user and needs to be"/>
   <int value="5" label="Network was not slow"/>
+  <int value="6" label="User opted out of this preview (pre-s13n only)"/>
 </enum>
 
 <enum name="PreviewsServerLitePageServerResponse">