Handle early pause, cancel for parallel requests.

content/browser/download/download_job.h

Index: content/browser/download/download_job.h
diff --git a/content/browser/download/download_job.h b/content/browser/download/download_job.h
index bd101c618d961c7213c4c4a1550e8261de4a434f..5bd4f7e1491f449273d0d9d93e397970bdb2a77a 100644
--- a/content/browser/download/download_job.h
+++ b/content/browser/download/download_job.h
@@ -27,11 +27,12 @@ class CONTENT_EXPORT DownloadJob {
 
   // Download operations.
   virtual void Start() = 0;
-  virtual void Cancel(bool user_cancel) = 0;
+  virtual void Cancel(bool user_cancel);
   virtual void Pause();
   virtual void Resume(bool resume_request);
 
   bool is_paused() const { return is_paused_; }
+  bool is_canceled() const { return is_canceled_; }
 
   // Return the WebContents associated with the download. Usually used to
   // associate a browser window for any UI that needs to be displayed to the
@@ -44,8 +45,9 @@ class CONTENT_EXPORT DownloadJob {
   void StartDownload() const;
   void Interrupt(DownloadInterruptReason reason);
 
-  // Add a byte stream to the download sink.
-  void AddByteStream(std::unique_ptr<ByteStreamReader> stream_reader,
+  // Add a byte stream to the download sink. Return false if we start to
+  // destroy download file.
+  bool AddByteStream(std::unique_ptr<ByteStreamReader> stream_reader,
                      int64_t offset,
                      int64_t length);
 
@@ -55,6 +57,9 @@ class CONTENT_EXPORT DownloadJob {
   // If the download progress is paused by the user.
   bool is_paused_;
 
+  // If the download progress is canceled.
+  bool is_canceled_;
+
   DISALLOW_COPY_AND_ASSIGN(DownloadJob);
 };