gdata: Introduce GDataWapiFeedLoader class

This class is introduced to separate code related to WAPI
(codename of Documents List API) feed loading.

To minimize diffs, the the class is defined in gdata_file_system.cc
The code will be moved to a set of new files in a separate patch.

BUG=130669
TEST=out/Release/unit_tests --gtest_filter=GData* && out/Release/browser_tests --gtest_filter=GData*

Review URL: https://chromiumcodereview.appspot.com/10828126

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@149591 0039d316-1c4b-4281-b951-d872f2087c98

chrome/browser/chromeos/gdata/gdata_file_system_unittest.cc

@@ -328,7 +328,7 @@ class GDataFileSystemTest : public testing::Test {
   bool UpdateContent(const std::vector<DocumentFeed*>& list,
                      int largest_changestamp) {
     GURL unused;
-    return file_system_->UpdateFromFeed(
+    return file_system_->UpdateFromFeedForTesting(
         list,
         largest_changestamp,
         root_feed_changestamp_++) == GDATA_FILE_OK;

chrome/browser/chromeos/gdata/gdata_files.cc

@@ -515,6 +515,13 @@ GDataEntry* GDataDirectoryService::FindEntryByPathSync(
   return NULL;
 }
 
+void GDataDirectoryService::FindEntryByPathAndRunSync(
+    const FilePath& search_file_path,
+    const FindEntryCallback& callback) {
+  GDataEntry* entry = FindEntryByPathSync(search_file_path);
+  callback.Run(entry ? GDATA_FILE_OK : GDATA_FILE_ERROR_NOT_FOUND, entry);
+}
+
 GDataEntry* GDataDirectoryService::GetEntryByResourceId(
     const std::string& resource) {
   // GDataFileSystem has already locked.

chrome/browser/chromeos/gdata/gdata_files.h

@@ -379,6 +379,11 @@ class GDataDirectoryService {
   // TODO(satorux): Replace this with an async version crbug.com/137160
   GDataEntry* FindEntryByPathSync(const FilePath& file_path);
 
+  // Searches for |file_path| synchronously, and runs |callback|.
+  // TODO(satorux): Replace this with an async version crbug.com/137160
+  void FindEntryByPathAndRunSync(const FilePath& file_path,
+                                 const FindEntryCallback& callback);
+
   // Returns the GDataEntry* with the corresponding |resource_id|.
   // TODO(achuith): Get rid of this in favor of async version crbug.com/13957.
   GDataEntry* GetEntryByResourceId(const std::string& resource_id);