Make the UI an observer of downloads.

content/browser/android/download_controller_android_impl.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.
 
 #include "content/browser/android/download_controller_android_impl.h"
 
 #include "base/android/jni_android.h"
 #include "base/android/jni_string.h"
 #include "base/bind.h"
 #include "base/logging.h"
@@ skipping 218 matching lines @@
   ScopedJavaLocalRef<jstring> jreferer =
       ConvertUTF8ToJavaString(env, info.referer);
 
   Java_DownloadController_newHttpGetDownload(
       env, GetJavaObject()->Controller(env).obj(), view.obj(), jurl.obj(),
       juser_agent.obj(), jcontent_disposition.obj(), jmime_type.obj(),
       jcookie.obj(), jreferer.obj(), info.total_bytes);
 }
 
 void DownloadControllerAndroidImpl::OnPostDownloadStarted(
-    WebContents* web_contents,
     DownloadItem* download_item) {
   DCHECK(BrowserThread::CurrentlyOn(BrowserThread::UI));
+  if (!download_item->GetWebContents())
+    return;
+
   JNIEnv* env = AttachCurrentThread();
 
   // Register for updates to the DownloadItem.
   download_item->AddObserver(this);
 
   ScopedJavaLocalRef<jobject> view =
-      GetContentViewCoreFromWebContents(web_contents);
+      GetContentViewCoreFromWebContents(download_item->GetWebContents());
   // The view went away. Can't proceed.
   if (view.is_null())
     return;
 
   Java_DownloadController_onHttpPostDownloadStarted(
       env, GetJavaObject()->Controller(env).obj(), view.obj());
 }
 
 void DownloadControllerAndroidImpl::OnDownloadUpdated(DownloadItem* item) {
   DCHECK(BrowserThread::CurrentlyOn(BrowserThread::UI));
 
-  if (item->GetState() != DownloadItem::COMPLETE)
+  if (!item->IsComplete())
     return;
 
+  // Multiple OnDownloadUpdated() notifications may be issued while the download
+  // is in the COMPLETE state. Only handle one.
+  item->RemoveObserver(this);
+
   // Call onHttpPostDownloadCompleted
   JNIEnv* env = AttachCurrentThread();
   ScopedJavaLocalRef<jstring> jurl =
       ConvertUTF8ToJavaString(env, item->GetURL().spec());
   ScopedJavaLocalRef<jstring> jcontent_disposition =
       ConvertUTF8ToJavaString(env, item->GetContentDisposition());
   ScopedJavaLocalRef<jstring> jmime_type =
       ConvertUTF8ToJavaString(env, item->GetMimeType());
   ScopedJavaLocalRef<jstring> jpath =
       ConvertUTF8ToJavaString(env, item->GetFullPath().value());
 
   ScopedJavaLocalRef<jobject> view_core = GetContentViewCoreFromWebContents(
       item->GetWebContents());
   if (view_core.is_null()) {
     // We can get NULL WebContents from the DownloadItem.
     return;
   }
 
   Java_DownloadController_onHttpPostDownloadCompleted(env,
       GetJavaObject()->Controller(env).obj(), view_core.obj(), jurl.obj(),
       jcontent_disposition.obj(), jmime_type.obj(), jpath.obj(),
       item->GetReceivedBytes(), true);
 }
 
-void DownloadControllerAndroidImpl::OnDownloadOpened(DownloadItem* item) {
-}
-
 ScopedJavaLocalRef<jobject> DownloadControllerAndroidImpl::GetContentView(
     int render_process_id, int render_view_id) {
   RenderViewHost* render_view_host =
       RenderViewHost::FromID(render_process_id, render_view_id);
 
   if (!render_view_host)
     return ScopedJavaLocalRef<jobject>();
 
   WebContents* web_contents =
       render_view_host->GetDelegate()->GetAsWebContents();
@@ skipping 50 matching lines @@
     referer = referer_url.spec();
   if (!request->url_chain().empty()) {
     original_url = request->url_chain().front();
     url = request->url_chain().back();
   }
 }
 
 DownloadControllerAndroidImpl::DownloadInfoAndroid::~DownloadInfoAndroid() {}
 
 }  // namespace content