Continue OnDownloadUpdated notifications after navigation (issue #1833)

libcef/browser/browser_host_impl.cc

@@ -1290,6 +1290,7 @@ void CefBrowserHostImpl::DestroyBrowser() {
   if (menu_manager_.get())
     menu_manager_->Destroy();
 
+  FOR_EACH_OBSERVER(Observer, observers_, OnBrowserDestroyed(this));
   platform_delegate_->BrowserDestroyed(this);
 
   while (!queued_messages_.empty()) {
@@ -2496,6 +2497,21 @@ bool CefBrowserHostImpl::Send(IPC::Message* message) {
   }
 }
 
+void CefBrowserHostImpl::AddObserver(Observer* observer) {
+  CEF_REQUIRE_UIT();
+  observers_.AddObserver(observer);
+}
+
+void CefBrowserHostImpl::RemoveObserver(Observer* observer) {
+  CEF_REQUIRE_UIT();
+  observers_.RemoveObserver(observer);
+}
+
+bool CefBrowserHostImpl::HasObserver(Observer* observer) const {
+  CEF_REQUIRE_UIT();
+  return observers_.HasObserver(observer);
+}
+
 
 // content::WebContentsObserver::OnMessageReceived() message handlers.
 // -----------------------------------------------------------------------------

libcef/browser/browser_host_impl.h

@@ -24,6 +24,7 @@
 #include "libcef/common/response_manager.h"
 
 #include "base/memory/scoped_ptr.h"
+#include "base/observer_list.h"
 #include "base/strings/string16.h"
 #include "base/synchronization/lock.h"
 #include "content/public/browser/notification_observer.h"
@@ -71,6 +72,18 @@ class CefBrowserHostImpl : public CefBrowserHost,
      virtual void OnResponse(const std::string& response) =0;
   };
 
+  // Interface to implement for observers that wish to be informed of changes
+  // to the CefBrowserHostImpl. All methods will be called on the UI thread.
+  class Observer {
+   public:
+    // Called before |browser| is destroyed. Any references to |browser| should
+    // be cleared when this method is called.
+    virtual void OnBrowserDestroyed(CefBrowserHostImpl* browser) =0;
+
+   protected:
+    virtual ~Observer() {}
+  };
+
   ~CefBrowserHostImpl() override;
 
   // Create a new CefBrowserHostImpl instance.
@@ -420,6 +433,13 @@ class CefBrowserHostImpl : public CefBrowserHost,
   // Override to provide a thread safe implementation.
   bool Send(IPC::Message* message) override;
 
+  // Manage observer objects. The observer must either outlive this object or
+  // remove itself before destruction. These methods can only be called on the
+  // UI thread.
+  void AddObserver(Observer* observer);
+  void RemoveObserver(Observer* observer);
+  bool HasObserver(Observer* observer) const;
+
  private:
   class DevToolsWebContentsObserver;
 
@@ -570,6 +590,9 @@ class CefBrowserHostImpl : public CefBrowserHost,
   // destroyed.
   CefDevToolsFrontend* devtools_frontend_;
 
+  // Observers that want to be notified of changes to this object.
+  base::ObserverList<Observer> observers_;
+
   IMPLEMENT_REFCOUNTING(CefBrowserHostImpl);
   DISALLOW_COPY_AND_ASSIGN(CefBrowserHostImpl);
 };

libcef/browser/download_manager_delegate.cc

@@ -5,9 +5,6 @@
 #include "libcef/browser/download_manager_delegate.h"
 
 #include "include/cef_download_handler.h"
-#include "libcef/browser/browser_context.h"
-#include "libcef/browser/browser_host_impl.h"
-#include "libcef/browser/context.h"
 #include "libcef/browser/download_item_impl.h"
 #include "libcef/browser/thread_util.h"
 
@@ -26,18 +23,8 @@ using content::DownloadItem;
 using content::DownloadManager;
 using content::WebContents;
 
-
 namespace {
 
-// Helper function to retrieve the CefBrowserHostImpl.
-CefRefPtr<CefBrowserHostImpl> GetBrowser(DownloadItem* item) {
-  content::WebContents* contents = item->GetWebContents();
-  if (!contents)
-    return NULL;
-
-  return CefBrowserHostImpl::GetBrowserForContents(contents).get();
-}
-
 // Helper function to retrieve the CefDownloadHandler.
 CefRefPtr<CefDownloadHandler> GetDownloadHandler(
     CefRefPtr<CefBrowserHostImpl> browser) {
@@ -274,10 +261,8 @@ CefDownloadManagerDelegate::CefDownloadManagerDelegate(
   DownloadManager::DownloadVector items;
   manager->GetAllDownloads(&items);
   DownloadManager::DownloadVector::const_iterator it = items.begin();
-  for (; it != items.end(); ++it) {
-    (*it)->AddObserver(this);
-    observing_.insert(*it);
-  }
+  for (; it != items.end(); ++it)
+    OnDownloadCreated(manager, *it);
 }
 
 CefDownloadManagerDelegate::~CefDownloadManagerDelegate() {
@@ -286,10 +271,8 @@ CefDownloadManagerDelegate::~CefDownloadManagerDelegate() {
     manager_->RemoveObserver(this);
   }
 
-  std::set<DownloadItem*>::const_iterator it = observing_.begin();
-  for (; it != observing_.end(); ++it)
-    (*it)->RemoveObserver(this);
-  observing_.clear();
+  while (!item_browser_map_.empty())
+    OnDownloadDestroyed(item_browser_map_.begin()->first);
 }
 
 void CefDownloadManagerDelegate::OnDownloadUpdated(
@@ -313,16 +296,52 @@ void CefDownloadManagerDelegate::OnDownloadUpdated(
 }
 
 void CefDownloadManagerDelegate::OnDownloadDestroyed(
-    DownloadItem* download) {
-  download->RemoveObserver(this);
-  observing_.erase(download);
+    DownloadItem* item) {
+  item->RemoveObserver(this);
+
+  CefBrowserHostImpl* browser = nullptr;
+
+  ItemBrowserMap::iterator it = item_browser_map_.find(item);
+  DCHECK(it != item_browser_map_.end());
+  if (it != item_browser_map_.end()) {
+    browser = it->second;
+    item_browser_map_.erase(it);
+  }
+
+  if (browser) {
+    // Determine if any remaining DownloadItems are associated with the same
+    // browser. If not, then unregister as an observer.
+    bool has_remaining = false;
+    ItemBrowserMap::const_iterator it2 = item_browser_map_.begin();
+    for (; it2 != item_browser_map_.end(); ++it2) {
+      if (it2->second == browser) {
+        has_remaining = true;
+        break;
+      }
+    }
+
+    if (!has_remaining)
+      browser->RemoveObserver(this);
+  }
 }
 
 void CefDownloadManagerDelegate::OnDownloadCreated(
     DownloadManager* manager,
     DownloadItem* item) {
   item->AddObserver(this);
-  observing_.insert(item);
+
+  CefBrowserHostImpl* browser = nullptr;
+  content::WebContents* contents = item->GetWebContents();
+  if (contents)
+    browser = CefBrowserHostImpl::GetBrowserForContents(contents).get();
+  DCHECK(browser);
+
+  item_browser_map_.insert(std::make_pair(item, browser));
+
+  // Register as an observer so that we can cancel associated DownloadItems when
+  // the browser is destroyed.
+  if (!browser->HasObserver(this))
+    browser->AddObserver(this);
 }
 
 void CefDownloadManagerDelegate::ManagerGoingDown(
@@ -379,3 +398,26 @@ void CefDownloadManagerDelegate::GetNextId(
   static uint32 next_id = DownloadItem::kInvalidId + 1;
   callback.Run(next_id++);
 }
+
+void CefDownloadManagerDelegate::OnBrowserDestroyed(
+    CefBrowserHostImpl* browser) {
+  ItemBrowserMap::iterator it = item_browser_map_.begin();
+  for (; it != item_browser_map_.end(); ++it) {
+    if (it->second == browser) {
+      // Don't call back into browsers that have been destroyed. We're not
+      // canceling the download so it will continue silently until it completes
+      // or until the associated browser context is destroyed.
+      it->second = nullptr;
+    }
+  }
+}
+
+CefBrowserHostImpl* CefDownloadManagerDelegate::GetBrowser(DownloadItem* item) {
+  ItemBrowserMap::const_iterator it = item_browser_map_.find(item);
+  if (it != item_browser_map_.end())
+    return it->second;
+
+  // An entry should always exist for a DownloadItem.
+  NOTREACHED();
+  return nullptr;
+}

libcef/browser/download_manager_delegate.h

@@ -8,6 +8,8 @@
 
 #include <set>
 
+#include "libcef/browser/browser_host_impl.h"
+
 #include "base/compiler_specific.h"
 #include "base/memory/weak_ptr.h"
 #include "content/public/browser/download_item.h"
@@ -17,15 +19,16 @@
 class CefDownloadManagerDelegate
     : public content::DownloadItem::Observer,
       public content::DownloadManager::Observer,
-      public content::DownloadManagerDelegate {
+      public content::DownloadManagerDelegate,
+      public CefBrowserHostImpl::Observer {
  public:
   explicit CefDownloadManagerDelegate(content::DownloadManager* manager);
   ~CefDownloadManagerDelegate() override;
 
  private:
   // DownloadItem::Observer methods.
-  void OnDownloadUpdated(content::DownloadItem* download) override;
-  void OnDownloadDestroyed(content::DownloadItem* download) override;
+  void OnDownloadUpdated(content::DownloadItem* item) override;
+  void OnDownloadDestroyed(content::DownloadItem* item) override;
 
   // DownloadManager::Observer methods.
   void OnDownloadCreated(content::DownloadManager* manager,
@@ -38,9 +41,19 @@ class CefDownloadManagerDelegate
       const content::DownloadTargetCallback& callback) override;
   void GetNextId(const content::DownloadIdCallback& callback) override;
 
+  // CefBrowserHostImpl::Observer methods.
+  void OnBrowserDestroyed(CefBrowserHostImpl* browser) override;
+
+  CefBrowserHostImpl* GetBrowser(content::DownloadItem* item);
+
   content::DownloadManager* manager_;
   base::WeakPtrFactory<content::DownloadManager> manager_ptr_factory_;
-  std::set<content::DownloadItem*> observing_;
+
+  // Map of DownloadItem to originating CefBrowserHostImpl. Maintaining this
+  // map is necessary because DownloadItem::GetWebContents() may return NULL if
+  // the browser navigates while the download is in progress.
+  typedef std::map<content::DownloadItem*, CefBrowserHostImpl* > ItemBrowserMap;
+  ItemBrowserMap item_browser_map_;
 
   DISALLOW_COPY_AND_ASSIGN(CefDownloadManagerDelegate);
 };