drive: Remove FileCacheObserver::OnCacheCommitted

FileCacheObserver::CommitDirty does nothing but notifying cache observers about OnCacheComitted event whose only user is SyncClient.
We should abandon this complexity by simply calling SyncClient methods from FileSystem.

Remove FileCacheObserver::OnCacheCommitted
Remove FileCache::CommitDirtyOnUIThread and StoreLocallyModifiedOnUIThread
Rename SyncClient methods.
Call SyncClient methods from FileSystem directly.
Add OperationObserver::OnCacheFileUploadNeededByOperation to trigger upload from CopyOperation.

BUG=247274
TEST=unit_tests

Review URL: https://chromiumcodereview.appspot.com/16628003

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@205568 0039d316-1c4b-4281-b951-d872f2087c98
diff --git a/chrome/browser/chromeos/drive/sync_client.cc b/chrome/browser/chromeos/drive/sync_client.cc
index f9f6bc0..42064d8 100644
--- a/chrome/browser/chromeos/drive/sync_client.cc
+++ b/chrome/browser/chromeos/drive/sync_client.cc
@@ -138,7 +138,13 @@
   pending_fetch_list_.erase(resource_id);
 }
 
-void SyncClient::OnCacheCommitted(const std::string& resource_id) {
+void SyncClient::AddFetchTask(const std::string& resource_id) {
+  DCHECK(BrowserThread::CurrentlyOn(BrowserThread::UI));
+
+  AddTaskToQueue(FETCH, resource_id);
+}
+
+void SyncClient::AddUploadTask(const std::string& resource_id) {
   DCHECK(BrowserThread::CurrentlyOn(BrowserThread::UI));
 
   AddTaskToQueue(UPLOAD, resource_id);