[Offline Pages] Download UI: Remove all observers when clearing cache.

components/offline_pages/core/downloads/download_ui_adapter.cc

 // 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 "components/offline_pages/core/downloads/download_ui_adapter.h"
 
 #include "base/bind.h"
 #include "base/guid.h"
 #include "base/logging.h"
 #include "base/memory/ptr_util.h"
@@ skipping 185 matching lines @@
 // comes back.
 void DownloadUIAdapter::LoadCache() {
   state_ = State::LOADING_PAGES;
   model_->GetAllPages(base::Bind(&DownloadUIAdapter::OnOfflinePagesLoaded,
                                  weak_ptr_factory_.GetWeakPtr()));
 }
 
 void DownloadUIAdapter::ClearCache() {
   // Once loaded, this class starts to observe the model. Only remove observer
   // if it was added.
-  if (state_ == State::LOADED)
+  if (state_ == State::LOADED) {
     model_->RemoveObserver(this);
+    request_coordinator_->RemoveObserver(this);
+  }
   items_.clear();
   state_ = State::NOT_LOADED;
 }
 
 void DownloadUIAdapter::OnOfflinePagesLoaded(
     const MultipleOfflinePageItemResult& pages) {
   // If multiple observers register quickly, the cache might be already loaded
   // by the previous LoadCache call. At the same time, if all observers already
   // left, there is no reason to populate the cache.
   if (state_ != State::LOADING_PAGES)
@@ skipping 84 matching lines @@
   items_.erase(it);
 
   if (state_ != State::LOADED)
     return;
 
   for (Observer& observer : observers_)
     observer.ItemDeleted(guid);
 }
 
 }  // namespace offline_pages