Get rid of RequestRegistry (part 3): remove Drive path from request objects.

chrome/browser/google_apis/request_registry.h

Index: chrome/browser/google_apis/request_registry.h
diff --git a/chrome/browser/google_apis/request_registry.h b/chrome/browser/google_apis/request_registry.h
index 0c034a7eb9d37c54784b514658ab0b8a8f66b00f..9374baa6f25f9f4059fe59e72a2f56658635007d 100644
--- a/chrome/browser/google_apis/request_registry.h
+++ b/chrome/browser/google_apis/request_registry.h
@@ -29,12 +29,10 @@ std::string RequestTransferStateToString(RequestTransferState state);
 
 // Structure that packs progress information of each request.
 struct RequestProgressStatus {
-  explicit RequestProgressStatus(const base::FilePath& file_path);
+  RequestProgressStatus();
 
   RequestID request_id;
 
-  // Drive path of the file dealt with the current request.
-  base::FilePath file_path;
   // Current state of the transfer;
   RequestTransferState transfer_state;
 };
@@ -53,7 +51,6 @@ class RequestRegistry {
   class Request {
    public:
     explicit Request(RequestRegistry* registry);
-    Request(RequestRegistry* registry, const base::FilePath& file_path);
     virtual ~Request();
 
     // Cancels the ongoing request. NotifyFinish() is called and the Request