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()|.
+  void set_start_offset(int64 bytes) { start_offset_ = bytes; }

[Randy Smith (Not in Mondays), 2011/11/15 18:45:26]

Can this be in the constructor?  And commented in a way that makes more sense
for this abstraction level?  From the viewpoint of the IO thread/DRH/RDH we're
just executing a request and piping the results across to the FILE & UI threads,
so this would just be "the offset in the resource targeted at which to start
downloading".

+
   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