Created a DownloadManager interface, for use in unit tests..

content/browser/download/download_file_manager.cc

Index: content/browser/download/download_file_manager.cc
diff --git a/content/browser/download/download_file_manager.cc b/content/browser/download/download_file_manager.cc
index 829cab9574981a6798665d55d6629ae3db74f3a5..cc79ffd1cfaaf5845834bcbfa2d9954172b8cc59 100644
--- a/content/browser/download/download_file_manager.cc
+++ b/content/browser/download/download_file_manager.cc
@@ -55,7 +55,7 @@ void DownloadFileManager::OnShutdown() {
 
 void DownloadFileManager::CreateDownloadFile(
     DownloadCreateInfo* info, const DownloadRequestHandle& request_handle,
-    DownloadManager* download_manager, bool get_hash) {
+    DownloadManagerInterface* download_manager, bool get_hash) {
   DCHECK(info);
   VLOG(20) << __FUNCTION__ << "()" << " info = " << info->DebugString();
   DCHECK(BrowserThread::CurrentlyOn(BrowserThread::FILE));
@@ -80,7 +80,7 @@ void DownloadFileManager::CreateDownloadFile(
 
   BrowserThread::PostTask(
       BrowserThread::UI, FROM_HERE,
-      base::Bind(&DownloadManager::StartDownload, download_manager,
+      base::Bind(&DownloadManagerInterface::StartDownload, download_manager,
                  info->download_id.local()));
 }
 
@@ -109,10 +109,10 @@ void DownloadFileManager::UpdateInProgressDownloads() {
        i != downloads_.end(); ++i) {
     DownloadId global_id = i->first;
     DownloadFile* download_file = i->second;
-    DownloadManager* manager = download_file->GetDownloadManager();
+    DownloadManagerInterface* manager = download_file->GetDownloadManager();
     if (manager) {
       BrowserThread::PostTask(BrowserThread::UI, FROM_HERE,
-          base::Bind(&DownloadManager::UpdateDownload, manager,
+          base::Bind(&DownloadManagerInterface::UpdateDownload, manager,
                      global_id.local(), download_file->bytes_so_far()));
     }
   }
@@ -123,7 +123,7 @@ void DownloadFileManager::StartDownload(
   DCHECK(BrowserThread::CurrentlyOn(BrowserThread::UI));
   DCHECK(info);
 
-  DownloadManager* manager = request_handle.GetDownloadManager();
+  DownloadManagerInterface* manager = request_handle.GetDownloadManager();
   if (!manager) {
     request_handle.CancelRequest();
     delete info;
@@ -162,7 +162,8 @@ void DownloadFileManager::UpdateDownload(
           download_file->AppendDataToFile(data->data(), data_len);
       if (write_result != net::OK) {
         // Write failed: interrupt the download.
-        DownloadManager* download_manager = download_file->GetDownloadManager();
+        DownloadManagerInterface* download_manager =
+            download_file->GetDownloadManager();
         had_error = true;
 
         int64 bytes_downloaded = download_file->bytes_so_far();
@@ -175,7 +176,7 @@ void DownloadFileManager::UpdateDownload(
         if (download_manager) {
           BrowserThread::PostTask(
               BrowserThread::UI, FROM_HERE,
-              base::Bind(&DownloadManager::OnDownloadInterrupted,
+              base::Bind(&DownloadManagerInterface::OnDownloadInterrupted,
                          download_manager, global_id.local(), bytes_downloaded,
                          ConvertNetErrorToInterruptReason(
                              write_result, DOWNLOAD_INTERRUPT_FROM_DISK)));
@@ -200,7 +201,8 @@ void DownloadFileManager::OnResponseCompleted(
 
   download_file->Finish();
 
-  DownloadManager* download_manager = download_file->GetDownloadManager();
+  DownloadManagerInterface* download_manager =
+      download_file->GetDownloadManager();
   if (!download_manager) {
     CancelDownload(global_id);
     return;
@@ -213,13 +215,13 @@ void DownloadFileManager::OnResponseCompleted(
   if (reason == DOWNLOAD_INTERRUPT_REASON_NONE) {
     BrowserThread::PostTask(
         BrowserThread::UI, FROM_HERE,
-        base::Bind(&DownloadManager::OnResponseCompleted,
+        base::Bind(&DownloadManagerInterface::OnResponseCompleted,
                    download_manager, global_id.local(),
                    download_file->bytes_so_far(), hash));
   } else {
     BrowserThread::PostTask(
         BrowserThread::UI, FROM_HERE,
-        base::Bind(&DownloadManager::OnDownloadInterrupted,
+        base::Bind(&DownloadManagerInterface::OnDownloadInterrupted,
                    download_manager, global_id.local(),
                    download_file->bytes_so_far(), reason));
   }
@@ -262,7 +264,8 @@ void DownloadFileManager::CompleteDownload(DownloadId global_id) {
   EraseDownload(global_id);
 }
 
-void DownloadFileManager::OnDownloadManagerShutdown(DownloadManager* manager) {
+void DownloadFileManager::OnDownloadManagerShutdown(
+    DownloadManagerInterface* manager) {
   DCHECK(BrowserThread::CurrentlyOn(BrowserThread::FILE));
   DCHECK(manager);
 
@@ -334,7 +337,8 @@ void DownloadFileManager::RenameCompletingDownloadFile(
     return;
 
   DCHECK(download_file->GetDownloadManager());
-  DownloadManager* download_manager = download_file->GetDownloadManager();
+  DownloadManagerInterface* download_manager =
+      download_file->GetDownloadManager();
 
   VLOG(20) << __FUNCTION__ << "()"
            << " download_file = " << download_file->DebugString();
@@ -372,7 +376,7 @@ void DownloadFileManager::RenameCompletingDownloadFile(
 
   BrowserThread::PostTask(
       BrowserThread::UI, FROM_HERE,
-      base::Bind(&DownloadManager::OnDownloadRenamedToFinalName,
+      base::Bind(&DownloadManagerInterface::OnDownloadRenamedToFinalName,
                  download_manager, global_id.local(), new_path, uniquifier));
 }
 
@@ -386,7 +390,8 @@ void DownloadFileManager::CancelDownloadOnRename(
   if (!download_file)
     return;
 
-  DownloadManager* download_manager = download_file->GetDownloadManager();
+  DownloadManagerInterface* download_manager =
+      download_file->GetDownloadManager();
   if (!download_manager) {
     // Without a download manager, we can't cancel the request normally, so we
     // need to do it here.  The normal path will also update the download
@@ -397,7 +402,7 @@ void DownloadFileManager::CancelDownloadOnRename(
 
   BrowserThread::PostTask(
       BrowserThread::UI, FROM_HERE,
-      base::Bind(&DownloadManager::OnDownloadInterrupted,
+      base::Bind(&DownloadManagerInterface::OnDownloadInterrupted,
                  download_manager, global_id.local(),
                  download_file->bytes_so_far(),
                  ConvertNetErrorToInterruptReason(