[ReadingList Offline] Handle AMP pages after the rendering delay.

ios/chrome/browser/reading_list/reading_list_distiller_page.mm

 // Copyright 2016 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 "ios/chrome/browser/reading_list/reading_list_distiller_page.h"
 
 #include "base/bind.h"
 #include "base/mac/foundation_util.h"
 #include "base/strings/utf_string_conversions.h"
 #include "base/threading/thread_task_runner_handle.h"
 #include "components/favicon/ios/web_favicon_driver.h"
 #include "components/google/core/browser/google_util.h"
 #include "ios/chrome/browser/reading_list/favicon_web_state_dispatcher_impl.h"
 #import "ios/web/public/navigation_item.h"
 #import "ios/web/public/navigation_manager.h"
 #include "ios/web/public/ssl_status.h"
 #import "ios/web/public/web_state/js/crw_js_injection_receiver.h"
 #import "ios/web/public/web_state/web_state.h"
 #import "net/base/mac/url_conversions.h"
 #include "net/cert/cert_status_flags.h"
 #include "url/url_constants.h"
 
 namespace {
-// The delay between the page load and the distillation in seconds.
-const int64_t kDistillationDelayInSeconds = 2;
+// The delay given to the web page to render after the PageLoaded callback.
+const int64_t kPageLoadDelayInSeconds = 2;
+
 const char* kGetIframeURLJavaScript =
     "document.getElementsByTagName('iframe')[0].src;";
 }  // namespace
 
 namespace reading_list {
 
 ReadingListDistillerPage::ReadingListDistillerPage(
     web::BrowserState* browser_state,
     FaviconWebStateDispatcher* web_state_dispatcher)
     : dom_distiller::DistillerPageIOS(browser_state),
@@ skipping 62 matching lines @@
   }
   return true;
 }
 
 void ReadingListDistillerPage::OnLoadURLDone(
     web::PageLoadCompletionStatus load_completion_status) {
   if (!IsLoadingSuccess(load_completion_status)) {
     DistillerPageIOS::OnLoadURLDone(load_completion_status);
     return;
   }
-  if (IsGoogleCachedAMPPage()) {
-    // Workaround for Google AMP pages.
-    HandleGoogleCachedAMPPage();
-  } else {
-    WaitForPageLoadCompletion();
-  }
-}
-
-void ReadingListDistillerPage::WaitForPageLoadCompletion() {
+  // Page is loaded but rendering may not be done yet. Give a delay to the page.
   base::WeakPtr<ReadingListDistillerPage> weak_this =
       weak_ptr_factory_.GetWeakPtr();
   base::ThreadTaskRunnerHandle::Get()->PostDelayedTask(
       FROM_HERE,
       base::Bind(&ReadingListDistillerPage::DelayedOnLoadURLDone, weak_this),
-      base::TimeDelta::FromSeconds(kDistillationDelayInSeconds));
+      base::TimeDelta::FromSeconds(kPageLoadDelayInSeconds));
 }
 
 void ReadingListDistillerPage::DelayedOnLoadURLDone() {
+  if (IsGoogleCachedAMPPage()) {
+    // Workaround for Google AMP pages.
+    HandleGoogleCachedAMPPage();
+  } else {
+    ContinuePageDistillation();
+  }
+}
+
+void ReadingListDistillerPage::ContinuePageDistillation() {
   // The page is ready to be distilled.
   // If the visible URL is not the original URL, notify the caller that URL
   // changed.
   GURL redirected_url = CurrentWebState()->GetVisibleURL();
   if (redirected_url != original_url_ && !redirection_callback_.is_null()) {
     redirection_callback_.Run(original_url_, redirected_url);
   }
   DistillerPageIOS::OnLoadURLDone(web::PageLoadCompletionStatus::SUCCESS);
 }
 
@@ skipping 27 matching lines @@
 void ReadingListDistillerPage::HandleGoogleCachedAMPPage() {
   base::WeakPtr<ReadingListDistillerPage> weak_this =
       weak_ptr_factory_.GetWeakPtr();
   [CurrentWebState()->GetJSInjectionReceiver()
       executeJavaScript:@(kGetIframeURLJavaScript)
       completionHandler:^(id result, NSError* error) {
         if (weak_this &&
             !weak_this->HandleGoogleCachedAMPPageJavaScriptResult(result,
                                                                   error)) {
           // If there is an error on navigation, continue normal distillation.
-          weak_this->WaitForPageLoadCompletion();
+          weak_this->ContinuePageDistillation();
         }
         // If there is no error, the navigation completion will trigger a new
         // |OnLoadURLDone| call that will resume the distillation.
       }];
 }
 
 bool ReadingListDistillerPage::HandleGoogleCachedAMPPageJavaScriptResult(
     id result,
     id error) {
   if (error) {
@@ skipping 15 matching lines @@
   GURL new_gurl = net::GURLWithNSURL(new_url);
   if (!new_gurl.is_valid()) {
     return false;
   }
   web::NavigationManager::WebLoadParams params(new_gurl);
   CurrentWebState()->GetNavigationManager()->LoadURLWithParams(params);
   return true;
 }
 
 }  // namespace reading_list