Create a Null DownloadRequestHandle for use by SavePackage DownloadItems.

content/browser/download/download_item.cc

 // Copyright (c) 2011 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_item.h"
 
 #include <vector>
 
 #include "base/bind.h"
 #include "base/basictypes.h"
@@ skipping 92 matching lines @@
 DownloadItem::DangerType GetDangerType(bool dangerous_file,
                                        bool dangerous_url) {
   if (dangerous_url) {
     // dangerous URL overweights dangerous file. We check dangerous URL first.
     return DownloadItem::DANGEROUS_URL;
   }
   return dangerous_file ?
       DownloadItem::DANGEROUS_FILE : DownloadItem::NOT_DANGEROUS;
 }
 
+// Classes to null out request handle calls (for SavePage DownloadItems, which
+// may have, e.g., Cancel() called on them without it doing anything)
+// and to DCHECK on them (for history DownloadItems, which should never have
+// any operation that implies an off-thread component, since they don't
+// have any).
+class NullDownloadRequestHandle : public DownloadRequestHandleInterface {
+ public:
+  NullDownloadRequestHandle() {}
+
+  // DownloadRequestHandleInterface calls
+  virtual TabContents* GetTabContents() const OVERRIDE {
+    return NULL;
+  }
+  virtual DownloadManager* GetDownloadManager() const OVERRIDE {
+    return NULL;
+  }
+  virtual void PauseRequest() const OVERRIDE {}
+  virtual void ResumeRequest() const OVERRIDE {}
+  virtual void CancelRequest() const OVERRIDE {}
+  virtual std::string DebugString() const OVERRIDE {
+    return "Null DownloadRequestHandle";
+  }
+};
+
+
 }  // namespace
 
 // Our download table ID starts at 1, so we use 0 to represent a download that
 // has started, but has not yet had its data persisted in the table. We use fake
 // database handles in incognito mode starting at -1 and progressively getting
 // more negative.
 // static
 const int DownloadItem::kUninitializedHandle = 0;
 
 // Constructor for reading from the history service.
@@ skipping 69 matching lines @@
       delegate_delayed_complete_(false) {
   Init(true /* actively downloading */);
 }
 
 // Constructing for the "Save Page As..." feature:
 DownloadItem::DownloadItem(DownloadManager* download_manager,
                            const FilePath& path,
                            const GURL& url,
                            bool is_otr,
                            DownloadId download_id)
-    : download_id_(download_id),
+    : request_handle_(new NullDownloadRequestHandle()),
+      download_id_(download_id),
       full_path_(path),
       url_chain_(1, url),
       referrer_url_(GURL()),
       total_bytes_(0),
       received_bytes_(0),
       last_reason_(DOWNLOAD_INTERRUPT_REASON_NONE),
       start_tick_(base::TimeTicks::Now()),
       state_(IN_PROGRESS),
       start_time_(base::Time::Now()),
       db_handle_(DownloadItem::kUninitializedHandle),
@@ skipping 487 matching lines @@
   return state_info_.target_name;
 }
 
 FilePath DownloadItem::GetUserVerifiedFilePath() const {
   return (safety_state_ == DownloadItem::SAFE) ?
       GetTargetFilePath() : full_path_;
 }
 
 void DownloadItem::OffThreadCancel(DownloadFileManager* file_manager) {
   DCHECK(BrowserThread::CurrentlyOn(BrowserThread::UI));
   request_handle_->CancelRequest();

[benjhayden, 2011/11/11 16:30:59]

Why not just if(request_handle_) here?

 
   BrowserThread::PostTask(BrowserThread::FILE, FROM_HERE,
                           base::Bind(&DownloadFileManager::CancelDownload,
                                      file_manager, global_id()));
 }
 
 void DownloadItem::Init(bool active) {
   // TODO(rdsmith): Change to DCHECK after http://crbug.com/85408 resolved.
   CHECK(BrowserThread::CurrentlyOn(BrowserThread::UI));
 
@@ skipping 74 matching lines @@
         state_info_.target_name.value().c_str(),
         full_path().value().c_str());
   } else {
     description += base::StringPrintf(" url = \"%s\"", url_list.c_str());
   }
 
   description += " }";
 
   return description;
 }