[Android Downloads] Long-press menu item "Download Link" should delegate job to OfflinePages backen…

content/browser/download/download_request_core.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/download/download_request_core.h"
 
 #include <string>
 
 #include "base/bind.h"
 #include "base/callback_helpers.h"
@@ skipping 27 matching lines @@
 #include "net/base/net_errors.h"
 #include "net/base/upload_bytes_element_reader.h"
 #include "net/http/http_response_headers.h"
 #include "net/http/http_status_code.h"
 #include "net/url_request/url_request_context.h"
 
 namespace content {
 
 namespace {
 
+// Mime type of download resource that should trigger handoff to OfflinePages
+// backend for full page load+snapshot.
+const char kHTMLType[] = "text/html";
+
 // This is a UserData::Data that will be attached to a URLRequest as a
 // side-channel for passing download parameters.
 class DownloadRequestData : public base::SupportsUserData::Data {
  public:
   ~DownloadRequestData() override {}
 
   static void Attach(net::URLRequest* request,
                      DownloadUrlParameters* download_parameters,
                      uint32_t download_id);
   static DownloadRequestData* Get(net::URLRequest* request);
@@ skipping 194 matching lines @@
   DCHECK_CURRENTLY_ON(BrowserThread::IO);
   DVLOG(20) << __func__ << "() " << DebugString();
   download_start_time_ = base::TimeTicks::Now();
 
   DownloadInterruptReason result =
       request()->response_headers()
           ? HandleSuccessfulServerResponse(*request()->response_headers(),
                                            save_info_.get())
           : DOWNLOAD_INTERRUPT_REASON_NONE;
 
+  // If the download resource is an HTML page, interrupt this download with
+  // a result code that allows handoff to the OfflinePage backend.
+  if (result == DOWNLOAD_INTERRUPT_REASON_NONE &&
+      override_mime_type == kHTMLType) {
+    result = DOWNLOAD_INTERRUPT_REASON_PAGE_DOWNLOAD_HANDOFF;

[jianli, 2016/11/23 01:27:32]

Do we want to return instead?

+  }
+
   std::unique_ptr<DownloadCreateInfo> create_info =
       CreateDownloadCreateInfo(result);
   if (result != DOWNLOAD_INTERRUPT_REASON_NONE) {
     delegate_->OnStart(std::move(create_info),
                        std::unique_ptr<ByteStreamReader>(),
                        base::ResetAndReturn(&on_started_callback_));
     return false;
   }
 
   // If it's a download, we don't want to poison the cache with it.
@@ skipping 355 matching lines @@
     return DOWNLOAD_INTERRUPT_REASON_NONE;
   }
 
   if (http_headers.response_code() == net::HTTP_PARTIAL_CONTENT)
     return DOWNLOAD_INTERRUPT_REASON_SERVER_BAD_CONTENT;
 
   return DOWNLOAD_INTERRUPT_REASON_NONE;
 }
 
 }  // namespace content