Implemented API for tracking ongoing file transfers from file manager.

new method:
chrome.fileManagerPrivate.getFileTransfers(function(transfers) {
});

new event:
chrome.fileManagerPrivate.onFileTransfersUpdated.addListener(function(transfers) {
});

where:

transfers = [
{
'fileUrl': 'filesystem://.../external/gdata/myfile.txt',
'transferState': 'started|in_progress|completed|failed',
'transferType': 'upload|download',
'processed': 1234,
'total': 54331
},
...
]

BUG=chromium-os:27819
TEST=none

Review URL: https://chromiumcodereview.appspot.com/9703042

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@127362 0039d316-1c4b-4281-b951-d872f2087c98
diff --git a/chrome/browser/extensions/extension_service.cc b/chrome/browser/extensions/extension_service.cc
index af61980d2..5b1258b 100644
--- a/chrome/browser/extensions/extension_service.cc
+++ b/chrome/browser/extensions/extension_service.cc
@@ -541,9 +541,8 @@
   web_navigation_event_router_->Init();
 
 #if defined(OS_CHROMEOS)
-  file_browser_event_router_.reset(
-      new ExtensionFileBrowserEventRouter(profile_));
-  file_browser_event_router_->ObserveFileSystemEvents();
+  FileBrowserEventRouterFactory::GetForProfile(
+      profile_)->ObserveFileSystemEvents();
 
   input_method_event_router_.reset(
       new chromeos::ExtensionInputMethodEventRouter);