[Offline pages] Stop observing web contents and reset to null after use. Only create a new web cont…

chrome/browser/android/offline_pages/background_loader_offliner.cc

Index: chrome/browser/android/offline_pages/background_loader_offliner.cc
diff --git a/chrome/browser/android/offline_pages/background_loader_offliner.cc b/chrome/browser/android/offline_pages/background_loader_offliner.cc
index 5e18f9ff775e7b475516983c5c80758c501e1a8c..4b5d23b335f9d913d671671ce9c45e3a682c79ba 100644
--- a/chrome/browser/android/offline_pages/background_loader_offliner.cc
+++ b/chrome/browser/android/offline_pages/background_loader_offliner.cc
@@ -149,8 +149,8 @@ bool BackgroundLoaderOffliner::LoadAndSave(
     return false;
   }
 
-  if (!loader_)
-    ResetState();
+  ResetLoader();
+  AttachObservers();
 
   // Track copy of pending request.
   pending_request_.reset(new SavePageRequest(request));
@@ -355,13 +355,16 @@ void BackgroundLoaderOffliner::ResetState() {
   snapshot_controller_.reset();
   page_load_state_ = SUCCESS;
   network_bytes_ = 0LL;
-  // TODO(chili): Remove after RequestCoordinator can handle multiple offliners.
-  // We reset the loader and observer after completion so loaders
-  // will not be re-used across different requests/tries. This is a temporary
-  // solution while there exists assumptions about the number of offliners
-  // there are.
+  content::WebContentsObserver::Observe(nullptr);
+  loader_.reset();
+}
+
+void BackgroundLoaderOffliner::ResetLoader() {
   loader_.reset(
       new background_loader::BackgroundLoaderContents(browser_context_));
+}
+
+void BackgroundLoaderOffliner::AttachObservers() {
   content::WebContents* contents = loader_->web_contents();
   content::WebContentsObserver::Observe(contents);
   OfflinerData::AddToWebContents(contents, this);