Added member data to classes to support download resumption.

content/browser/download/download_resource_handler.h

Index: content/browser/download/download_resource_handler.h
diff --git a/content/browser/download/download_resource_handler.h b/content/browser/download/download_resource_handler.h
index 016756c58ad68c336a0055f310e8f0db903b5f23..b454547c211c87f3fed738a21bde65f33c72fbac 100644
--- a/content/browser/download/download_resource_handler.h
+++ b/content/browser/download/download_resource_handler.h
@@ -11,10 +11,11 @@
 #include "base/callback.h"
 #include "base/memory/scoped_ptr.h"
 #include "base/timer.h"
-#include "content/browser/download/download_file.h"
 #include "content/browser/download/download_id.h"
+#include "content/browser/download/download_types.h"
 #include "content/browser/renderer_host/global_request_id.h"
 #include "content/browser/renderer_host/resource_handler.h"
+#include "net/base/net_errors.h"
 
 class DownloadFileManager;
 class ResourceDispatcherHost;
@@ -79,6 +80,10 @@ class DownloadResourceHandler : public ResourceHandler {
 
   void set_content_disposition(const std::string& content_disposition);
 
+  // How many bytes were read before this request was interrupted. Should be
+  // used only by |ResourceDispatcherHost::BeginDownload()|.

[Randy Smith (Not in Mondays), 2011/11/16 18:29:27]

I'd like to think about the interface to the IO and file threads as being just
about the current request, and how they're used (to pick up where we left off)
being in the UI thread/DownloadItem.  So this comment should just say something
like "Location within the remote resource at which to start the download."

[ahendrickson, 2011/11/19 20:18:03]

Done.

+  void set_start_offset(int64 bytes) { start_offset_ = bytes; }
+
   void CheckWriteProgress();
 
   std::string DebugString() const;
@@ -107,6 +112,7 @@ class DownloadResourceHandler : public ResourceHandler {
   base::TimeTicks download_start_time_;  // used to collect stats.
   base::TimeTicks last_read_time_;        // used to collect stats.
   size_t last_buffer_size_;               // used to collect stats.
+  int64 start_offset_;
   static const int kReadBufSize = 32768;  // bytes
   static const int kThrottleTimeMs = 200;  // milliseconds