Add new UMA stats for parallelizable download

content/browser/download/download_job_impl.h

Index: content/browser/download/download_job_impl.h
diff --git a/content/browser/download/download_job_impl.h b/content/browser/download/download_job_impl.h
index c24f92d4440a45a5d34db2c1daebcc4a127d2c35..59522a7193f79906995faacb8c6220272fee27e4 100644
--- a/content/browser/download/download_job_impl.h
+++ b/content/browser/download/download_job_impl.h
@@ -17,7 +17,8 @@ class CONTENT_EXPORT DownloadJobImpl : public DownloadJob {
  public:
   DownloadJobImpl(
       DownloadItemImpl* download_item,
-      std::unique_ptr<DownloadRequestHandleInterface> request_handle);
+      std::unique_ptr<DownloadRequestHandleInterface> request_handle,
+      bool is_parallizable);
   ~DownloadJobImpl() override;
 
   // DownloadJob implementation.
@@ -26,12 +27,16 @@ class CONTENT_EXPORT DownloadJobImpl : public DownloadJob {
   void Pause() override;
   void Resume(bool resume_request) override;
   WebContents* GetWebContents() const override;
+  bool IsParallelizable() const override;
 
  private:
   // Used to perform operations on network request.
   // Can be null on interrupted download.
   std::unique_ptr<DownloadRequestHandleInterface> request_handle_;
 
+  // Whether the download can be parallized.
+  bool is_parallizable_;
+
   DISALLOW_COPY_AND_ASSIGN(DownloadJobImpl);
 };