[MediaGalleries] Enable iPhoto gallery

chrome/browser/media_galleries/media_file_system_registry.cc

 // Copyright (c) 2012 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.
 
 // MediaFileSystemRegistry implementation.
 
 #include "chrome/browser/media_galleries/media_file_system_registry.h"
 
 #include <set>
 #include <vector>
@@ skipping 130 matching lines @@
       }
       default: {
         NOTREACHED();
         break;
       }
     }
   }
 
   void OnRendererProcessTerminated(const RenderProcessHost* rph) {
     RPHRefCount::iterator rph_info = refs_.find(rph);
-    DCHECK(rph_info != refs_.end());
+    // This could be a potential problem if the RPH is navigated to
+    // a page on the same renderer (triggering OWCDON()) and then
+    // the renderer crashes.
+    if (rph_info == refs_.end()) {
+      NOTREACHED();
+      return;
+    }
+
     delete rph_info->second;
     refs_.erase(rph_info);
     if (refs_.empty())
       no_references_callback_.Run();
   }
 
   void OnWebContentsDestroyedOrNavigated(const WebContents* contents) {
     RenderProcessHost* rph = contents->GetRenderProcessHost();
     RPHRefCount::iterator rph_info = refs_.find(rph);
     DCHECK(rph_info != refs_.end());
@@ skipping 118 matching lines @@
 
  private:
   typedef std::map<MediaGalleryPrefId, MediaFileSystemInfo> PrefIdFsInfoMap;
 
   // Private destructor and friend declaration for ref counted implementation.
   friend class base::RefCountedThreadSafe<ExtensionGalleriesHost>;
 
   virtual ~ExtensionGalleriesHost() {
     DCHECK(rph_refs_.empty());
     DCHECK(pref_id_map_.empty());
-
   }
 
   void GetMediaFileSystemsForAttachedDevices(
       const MediaStorageUtil::DeviceIdSet* attached_devices,
       const MediaGalleryPrefIdSet& galleries,
       const MediaGalleriesPrefInfoMap& galleries_info,
       const MediaFileSystemsCallback& callback) {
     std::vector<MediaFileSystemInfo> result;
+
+    if (rph_refs_.empty()) {
+      // We're actually in the middle of shutdown, and Filter...() lagging
+      // which can invoke this method interleaved in the destruction callback
+      // sequence and re-populate pref_id_map_.
+      callback.Run(result);
+      return;
+    }
+
     MediaGalleryPrefIdSet new_galleries;
     for (std::set<MediaGalleryPrefId>::const_iterator pref_id_it =
              galleries.begin();
          pref_id_it != galleries.end();
          ++pref_id_it) {
       const MediaGalleryPrefId& pref_id = *pref_id_it;
       const MediaGalleryPrefInfo& gallery_info =
           galleries_info.find(pref_id)->second;
       const std::string& device_id = gallery_info.device_id;
       if (!ContainsKey(*attached_devices, device_id))
@@ skipping 105 matching lines @@
       extension_hosts->second[extension->id()].get();
   if (!extension_host) {
     extension_host = new ExtensionGalleriesHost(
         file_system_context_.get(),
         base::Bind(&MediaFileSystemRegistry::OnExtensionGalleriesHostEmpty,
                    base::Unretained(this),
                    profile,
                    extension->id()));
     extension_hosts_map_[profile][extension->id()] = extension_host;
   }
+  // This must come before the GetMediaFileSystems call to make sure the
+  // RVH of the context is referenced before the filesystems are retrieved.
   extension_host->ReferenceFromRVH(rvh);
 
   extension_host->GetMediaFileSystems(galleries, preferences->known_galleries(),
                                       callback);
 }
 
 MediaGalleriesPreferences* MediaFileSystemRegistry::GetPreferences(
     Profile* profile) {
   // Create an empty ExtensionHostMap for this profile on first initialization.
   if (!ContainsKey(extension_hosts_map_, profile))
@@ skipping 232 matching lines @@
   DCHECK_EQ(1U, erase_count);
   if (extension_hosts->second.empty()) {
     // When a profile has no ExtensionGalleriesHosts left, remove the
     // matching gallery-change-watcher since it is no longer needed. Leave the
     // |extension_hosts| entry alone, since it indicates the profile has been
     // previously used.
     MediaGalleriesPreferences* preferences = GetPreferences(profile);
     preferences->RemoveGalleryChangeObserver(this);
   }
 }