Delete gdata::FindEntryDelegate

Replace all FindEntryDelegate subclasses with ReadOnlyFindEntryCallback and FindEntryCallback
Move FindEntryCallback to find_entry_callback.h

BUG=127028
TEST=unit_tests --gtest_filter="GData*"

Review URL: https://chromiumcodereview.appspot.com/10310077

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@136508 0039d316-1c4b-4281-b951-d872f2087c98

13 files changed, 126 insertions, 232 deletions

diff --git a/chrome/browser/chromeos/gdata/find_entry_callback.cc b/chrome/browser/chromeos/gdata/find_entry_callback.cc
new file mode 100644
index 0000000..2edd47d
--- /dev/null
+++ b/chrome/browser/chromeos/gdata/find_entry_callback.cc
@@ -0,0 +1,17 @@
+// Copyright (c) 2012 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#include "chrome/browser/chromeos/gdata/find_entry_callback.h"
+
+namespace gdata {
+
+void ReadOnlyFindEntryCallback(GDataEntry** out,
+                               base::PlatformFileError error,
+                               const FilePath& directory_path,
+                               GDataEntry* entry) {
+  if (error == base::PLATFORM_FILE_OK)
+    *out = entry;
+}
+
+}  // namespace gdata
diff --git a/chrome/browser/chromeos/gdata/find_entry_callback.h b/chrome/browser/chromeos/gdata/find_entry_callback.h
new file mode 100644
index 0000000..f0e344c
--- /dev/null
+++ b/chrome/browser/chromeos/gdata/find_entry_callback.h
@@ -0,0 +1,33 @@
+// Copyright (c) 2012 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#ifndef CHROME_BROWSER_CHROMEOS_GDATA_FIND_ENTRY_CALLBACK_H_
+#define CHROME_BROWSER_CHROMEOS_GDATA_FIND_ENTRY_CALLBACK_H_
+#pragma once
+
+#include "base/callback.h"
+#include "base/platform_file.h"
+
+namespace gdata {
+
+class GDataEntry;
+
+// Used to get result of file search. Please note that |file| is a live
+// object provided to this callback under lock. It must not be used outside
+// of the callback method. This callback can be invoked on different thread
+// than one that started the request.
+typedef base::Callback<void(base::PlatformFileError error,
+                            const FilePath& directory_path,
+                            GDataEntry* entry)>
+    FindEntryCallback;
+
+// Callback used to find a directory element for file system updates.
+void ReadOnlyFindEntryCallback(GDataEntry** out,
+                               base::PlatformFileError error,
+                               const FilePath& directory_path,
+                               GDataEntry* entry);
+
+}  // namespace gdata
+
+#endif  // CHROME_BROWSER_CHROMEOS_GDATA_FIND_ENTRY_CALLBACK_H_
diff --git a/chrome/browser/chromeos/gdata/find_entry_delegate.cc b/chrome/browser/chromeos/gdata/find_entry_delegate.cc
deleted file mode 100644
index f91e3d1..0000000
--- a/chrome/browser/chromeos/gdata/find_entry_delegate.cc
+++ /dev/null
@@ -1,41 +0,0 @@
-// Copyright (c) 2012 The Chromium Authors. All rights reserved.
-// Use of this source code is governed by a BSD-style license that can be
-// found in the LICENSE file.
-
-#include "chrome/browser/chromeos/gdata/find_entry_delegate.h"
-
-#include "chrome/browser/chromeos/gdata/gdata_files.h"
-
-namespace gdata {
-
-FindEntryDelegate::~FindEntryDelegate() {
-}
-
-ReadOnlyFindEntryDelegate::ReadOnlyFindEntryDelegate() : entry_(NULL) {
-}
-
-void ReadOnlyFindEntryDelegate::OnDone(base::PlatformFileError error,
-                                       const FilePath& directory_path,
-                                       GDataEntry* entry) {
-  DCHECK(!entry_);
-  if (error == base::PLATFORM_FILE_OK)
-    entry_ = entry;
-  else
-    entry_ = NULL;
-}
-
-FindEntryCallbackRelayDelegate::FindEntryCallbackRelayDelegate(
-    const FindEntryCallback& callback) : callback_(callback) {
-}
-
-FindEntryCallbackRelayDelegate::~FindEntryCallbackRelayDelegate() {
-}
-
-void FindEntryCallbackRelayDelegate::OnDone(base::PlatformFileError error,
-                                            const FilePath& directory_path,
-                                            GDataEntry* entry) {
-  if (!callback_.is_null())
-    callback_.Run(error, directory_path, entry);
-}
-
-}  // namespace gdata
diff --git a/chrome/browser/chromeos/gdata/find_entry_delegate.h b/chrome/browser/chromeos/gdata/find_entry_delegate.h
deleted file mode 100644
index e5f3e23..0000000
--- a/chrome/browser/chromeos/gdata/find_entry_delegate.h
+++ /dev/null
@@ -1,76 +0,0 @@
-// Copyright (c) 2012 The Chromium Authors. All rights reserved.
-// Use of this source code is governed by a BSD-style license that can be
-// found in the LICENSE file.
-
-#ifndef CHROME_BROWSER_CHROMEOS_GDATA_FIND_ENTRY_DELEGATE_H_
-#define CHROME_BROWSER_CHROMEOS_GDATA_FIND_ENTRY_DELEGATE_H_
-#pragma once
-
-#include "base/bind.h"
-#include "base/platform_file.h"
-
-class FilePath;
-
-namespace gdata {
-
-class GDataEntry;
-
-// Used to get result of file search. Please note that |file| is a live
-// object provided to this callback under lock. It must not be used outside
-// of the callback method. This callback can be invoked on different thread
-// than one that started the request.
-typedef base::Callback<void(base::PlatformFileError error,
-                            const FilePath& directory_path,
-                            GDataEntry* entry)>
-    FindEntryCallback;
-
-// Delegate class used to deal with results synchronous read-only search
-// over virtual file system.
-class FindEntryDelegate {
- public:
-  virtual ~FindEntryDelegate();
-
-  // Called when GDataRootDirectory::FindEntryByPath() completes search.
-  virtual void OnDone(base::PlatformFileError error,
-                      const FilePath& directory_path,
-                      GDataEntry* entry) = 0;
-};
-
-// Delegate used to find a directory element for file system updates.
-class ReadOnlyFindEntryDelegate : public FindEntryDelegate {
- public:
-  ReadOnlyFindEntryDelegate();
-
-  // Returns found entry.
-  GDataEntry* entry() { return entry_; }
-
- private:
-  // FindEntryDelegate overrides.
-  virtual void OnDone(base::PlatformFileError error,
-                      const FilePath& directory_path,
-                      GDataEntry* entry) OVERRIDE;
-
-  // Entry that was found.
-  GDataEntry* entry_;
-};
-
-// FindEntryCallbackRelayDelegate class implementation.
-// This class is used to relay calls between sync and async versions
-// of FindFileByPath(Sync|Async) calls.
-class FindEntryCallbackRelayDelegate : public FindEntryDelegate {
- public:
-  explicit FindEntryCallbackRelayDelegate(const FindEntryCallback& callback);
-  virtual ~FindEntryCallbackRelayDelegate();
-
- private:
-  // FindEntryDelegate overrides.
-  virtual void OnDone(base::PlatformFileError error,
-                      const FilePath& directory_path,
-                      GDataEntry* entry) OVERRIDE;
-
-  const FindEntryCallback callback_;
-};
-
-}  // namespace gdata
-
-#endif  // CHROME_BROWSER_CHROMEOS_GDATA_FIND_ENTRY_DELEGATE_H_
diff --git a/chrome/browser/chromeos/gdata/gdata_file_system.cc b/chrome/browser/chromeos/gdata/gdata_file_system.cc
index b1c9a91..d329e9e 100644
--- a/chrome/browser/chromeos/gdata/gdata_file_system.cc
+++ b/chrome/browser/chromeos/gdata/gdata_file_system.cc
@@ -1108,7 +1108,7 @@ void GDataFileSystem::Authenticate(const AuthStatusCallback& callback) {
 
 void GDataFileSystem::FindEntryByResourceIdSync(
     const std::string& resource_id,
-    FindEntryDelegate* delegate) {
+    const FindEntryCallback& callback) {
   base::AutoLock lock(lock_);  // To access the cache map.
 
   GDataFile* file = NULL;
@@ -1116,12 +1116,10 @@ void GDataFileSystem::FindEntryByResourceIdSync(
   if (entry)
     file = entry->AsGDataFile();
 
-  if (file) {
-    delegate->OnDone(base::PLATFORM_FILE_OK, file->parent()->GetFilePath(),
-                     file);
-  } else {
-    delegate->OnDone(base::PLATFORM_FILE_ERROR_NOT_FOUND, FilePath(), NULL);
-  }
+  if (file)
+    callback.Run(base::PLATFORM_FILE_OK, file->parent()->GetFilePath(), file);
+  else
+    callback.Run(base::PLATFORM_FILE_ERROR_NOT_FOUND, FilePath(), NULL);
 }
 
 void GDataFileSystem::FindEntryByPathAsyncOnUIThread(
@@ -1167,8 +1165,7 @@ void GDataFileSystem::FindEntryByPathSyncOnUIThread(
   DCHECK(BrowserThread::CurrentlyOn(BrowserThread::UI));
 
   base::AutoLock lock(lock_);  // To access root_.
-  FindEntryCallbackRelayDelegate delegate(callback);
-  root_->FindEntryByPath(search_file_path, &delegate);
+  root_->FindEntryByPath(search_file_path, callback);
 }
 
 void GDataFileSystem::ReloadFeedFromServerIfNeeded(
@@ -2566,9 +2563,10 @@ GDataEntry* GDataFileSystem::GetGDataEntryByPath(
     const FilePath& file_path) {
   lock_.AssertAcquired();
   // Find directory element within the cached file system snapshot.
-  ReadOnlyFindEntryDelegate find_delegate;
-  root_->FindEntryByPath(file_path, &find_delegate);
-  return find_delegate.entry();
+  GDataEntry* entry = NULL;
+  root_->FindEntryByPath(file_path, base::Bind(&ReadOnlyFindEntryCallback,
+                                               &entry));
+  return entry;
 }
 
 void GDataFileSystem::GetCacheState(const std::string& resource_id,
diff --git a/chrome/browser/chromeos/gdata/gdata_file_system.h b/chrome/browser/chromeos/gdata/gdata_file_system.h
index 28f481f..d9370ae 100644
--- a/chrome/browser/chromeos/gdata/gdata_file_system.h
+++ b/chrome/browser/chromeos/gdata/gdata_file_system.h
@@ -21,7 +21,7 @@
 #include "base/timer.h"
 #include "base/synchronization/lock.h"
 #include "base/threading/sequenced_worker_pool.h"
-#include "chrome/browser/chromeos/gdata/find_entry_delegate.h"
+#include "chrome/browser/chromeos/gdata/find_entry_callback.h"
 #include "chrome/browser/chromeos/gdata/gdata_documents_service.h"
 #include "chrome/browser/chromeos/gdata/gdata_files.h"
 #include "chrome/browser/chromeos/gdata/gdata_operation_registry.h"
@@ -210,13 +210,13 @@ class GDataFileSystemInterface {
   virtual void Authenticate(const AuthStatusCallback& callback) = 0;
 
   // Finds file info by using |resource_id|. This call does not initiate
-  // content refreshing and will invoke one of |delegate| methods directly as
+  // content refreshing and will invoke one of |callback| methods directly as
   // it executes.
   //
-  // Can be called from UI/IO thread. |delegate| is run on the calling thread
+  // Can be called from UI/IO thread. |callback| is run on the calling thread
   // synchronously.
   virtual void FindEntryByResourceIdSync(const std::string& resource_id,
-                                         FindEntryDelegate* delegate) = 0;
+                                         const FindEntryCallback& callback) = 0;
 
   // Initiates transfer of |remote_src_file_path| to |local_dest_file_path|.
   // |remote_src_file_path| is the virtual source path on the gdata file system.
@@ -437,8 +437,9 @@ class GDataFileSystem : public GDataFileSystemInterface,
   virtual void StopUpdates() OVERRIDE;
   virtual void CheckForUpdates() OVERRIDE;
   virtual void Authenticate(const AuthStatusCallback& callback) OVERRIDE;
-  virtual void FindEntryByResourceIdSync(const std::string& resource_id,
-                                         FindEntryDelegate* delegate) OVERRIDE;
+  virtual void FindEntryByResourceIdSync(
+      const std::string& resource_id,
+      const FindEntryCallback& callback) OVERRIDE;
   virtual void SearchAsync(const std::string& search_query,
                            const ReadDirectoryCallback& callback) OVERRIDE;
   virtual void TransferFileFromRemoteToLocal(
diff --git a/chrome/browser/chromeos/gdata/gdata_file_system_unittest.cc b/chrome/browser/chromeos/gdata/gdata_file_system_unittest.cc
index 66915ac..0efffbf 100644
--- a/chrome/browser/chromeos/gdata/gdata_file_system_unittest.cc
+++ b/chrome/browser/chromeos/gdata/gdata_file_system_unittest.cc
@@ -292,9 +292,10 @@ class GDataFileSystemTest : public testing::Test {
   }
 
   GDataEntry* FindEntry(const FilePath& file_path) {
-    ReadOnlyFindEntryDelegate search_delegate;
-    file_system_->root_->FindEntryByPath(file_path, &search_delegate);
-    return search_delegate.entry();
+    GDataEntry* entry = NULL;
+    file_system_->root_->FindEntryByPath(
+        file_path, base::Bind(&ReadOnlyFindEntryCallback, &entry));
+    return entry;
   }
 
   void FindAndTestFilePath(const FilePath& file_path) {
@@ -304,10 +305,10 @@ class GDataFileSystemTest : public testing::Test {
   }
 
   GDataEntry* FindEntryByResourceId(const std::string& resource_id) {
-    ReadOnlyFindEntryDelegate search_delegate;
-    file_system_->FindEntryByResourceIdSync(resource_id,
-                                            &search_delegate);
-    return search_delegate.entry();
+    GDataEntry* entry = NULL;
+    file_system_->FindEntryByResourceIdSync(
+        resource_id, base::Bind(&ReadOnlyFindEntryCallback, &entry));
+    return entry;
   }
 
   // Gets the entry info for |file_path| and compares the contents against
diff --git a/chrome/browser/chromeos/gdata/gdata_files.cc b/chrome/browser/chromeos/gdata/gdata_files.cc
index 83182bb..a1350d8 100644
--- a/chrome/browser/chromeos/gdata/gdata_files.cc
+++ b/chrome/browser/chromeos/gdata/gdata_files.cc
@@ -8,7 +8,6 @@
 #include "base/platform_file.h"
 #include "base/stringprintf.h"
 #include "base/string_util.h"
-#include "chrome/browser/chromeos/gdata/find_entry_delegate.h"
 #include "chrome/browser/chromeos/gdata/gdata.pb.h"
 #include "chrome/browser/chromeos/gdata/gdata_parser.h"
 #include "chrome/browser/chromeos/gdata/gdata_util.h"
@@ -504,11 +503,10 @@ bool GDataRootDirectory::ModifyFindEntryParamsForSearchPath(
   return true;
 }
 
-void GDataRootDirectory::FindEntryByPath(
-    const FilePath& file_path,
-    FindEntryDelegate* delegate) {
+void GDataRootDirectory::FindEntryByPath(const FilePath& file_path,
+                                         const FindEntryCallback& callback) {
   // GDataFileSystem has already locked.
-  DCHECK(delegate);
+  DCHECK(!callback.is_null());
 
   std::vector<FilePath::StringType> components;
   file_path.GetComponents(&components);
@@ -521,8 +519,8 @@ void GDataRootDirectory::FindEntryByPath(
 
   if (path_type == util::GDATA_SEARCH_PATH_ROOT ||
       path_type == util::GDATA_SEARCH_PATH_QUERY) {
-    delegate->OnDone(base::PLATFORM_FILE_OK, file_path.DirName(),
-                     fake_search_directory_.get());
+    callback.Run(base::PLATFORM_FILE_OK, file_path.DirName(),
+                 fake_search_directory_.get());
     return;
   }
 
@@ -531,7 +529,7 @@ void GDataRootDirectory::FindEntryByPath(
   if (path_type != util::GDATA_SEARCH_PATH_INVALID) {
     if (!ModifyFindEntryParamsForSearchPath(file_path,
              &components, &current_dir, &directory_path)) {
-      delegate->OnDone(base::PLATFORM_FILE_ERROR_NOT_FOUND, FilePath(), NULL);
+      callback.Run(base::PLATFORM_FILE_ERROR_NOT_FOUND, FilePath(), NULL);
       return;
     }
   }
@@ -541,18 +539,17 @@ void GDataRootDirectory::FindEntryByPath(
 
     // Last element must match, if not last then it must be a directory.
     if (i == components.size() - 1) {
-      if (current_dir->file_name() == components[i]) {
-        delegate->OnDone(base::PLATFORM_FILE_OK, directory_path, current_dir);
-      } else {
-        delegate->OnDone(base::PLATFORM_FILE_ERROR_NOT_FOUND, FilePath(), NULL);
-      }
+      if (current_dir->file_name() == components[i])
+        callback.Run(base::PLATFORM_FILE_OK, directory_path, current_dir);
+      else
+        callback.Run(base::PLATFORM_FILE_ERROR_NOT_FOUND, FilePath(), NULL);
       return;
     }
 
     // Not the last part of the path, search for the next segment.
     GDataEntry* entry = current_dir->FindChild(components[i + 1]);
     if (!entry) {
-      delegate->OnDone(base::PLATFORM_FILE_ERROR_NOT_FOUND, FilePath(), NULL);
+      callback.Run(base::PLATFORM_FILE_ERROR_NOT_FOUND, FilePath(), NULL);
       return;
     }
 
@@ -561,18 +558,15 @@ void GDataRootDirectory::FindEntryByPath(
       // Found directory, continue traversal.
       current_dir = entry->AsGDataDirectory();
     } else {
-      if ((i + 1) == (components.size() - 1)) {
-        delegate->OnDone(base::PLATFORM_FILE_OK,
-                         directory_path,
-                         entry);
-      } else {
-        delegate->OnDone(base::PLATFORM_FILE_ERROR_NOT_FOUND, FilePath(), NULL);
-      }
+      if ((i + 1) == (components.size() - 1))
+        callback.Run(base::PLATFORM_FILE_OK, directory_path, entry);
+      else
+        callback.Run(base::PLATFORM_FILE_ERROR_NOT_FOUND, FilePath(), NULL);
 
       return;
     }
   }
-  delegate->OnDone(base::PLATFORM_FILE_ERROR_NOT_FOUND, FilePath(), NULL);
+  callback.Run(base::PLATFORM_FILE_ERROR_NOT_FOUND, FilePath(), NULL);
 }
 
 GDataEntry* GDataRootDirectory::GetEntryByResourceId(
diff --git a/chrome/browser/chromeos/gdata/gdata_files.h b/chrome/browser/chromeos/gdata/gdata_files.h
index 51e9660..6b7e01d 100644
--- a/chrome/browser/chromeos/gdata/gdata_files.h
+++ b/chrome/browser/chromeos/gdata/gdata_files.h
@@ -17,6 +17,7 @@
 #include "base/memory/weak_ptr.h"
 #include "base/platform_file.h"
 #include "base/synchronization/lock.h"
+#include "chrome/browser/chromeos/gdata/find_entry_callback.h"
 #include "chrome/browser/chromeos/gdata/gdata_params.h"
 #include "chrome/browser/chromeos/gdata/gdata_parser.h"
 #include "chrome/browser/chromeos/gdata/gdata_uploader.h"
@@ -25,7 +26,6 @@
 
 namespace gdata {
 
-class FindEntryDelegate;
 class GDataFile;
 class GDataDirectory;
 class GDataRootDirectory;
@@ -460,9 +460,9 @@ class GDataRootDirectory : public GDataDirectory {
   // Removes the entry from resource map.
   void RemoveEntryFromResourceMap(GDataEntry* entry);
 
-  // Searches for |file_path| triggering callback in |delegate|.
+  // Searches for |file_path| triggering callback.
   void FindEntryByPath(const FilePath& file_path,
-                       FindEntryDelegate* delegate);
+                       const FindEntryCallback& callback);
 
   // Returns the GDataEntry* with the corresponding |resource_id|.
   GDataEntry* GetEntryByResourceId(const std::string& resource_id);
diff --git a/chrome/browser/chromeos/gdata/gdata_protocol_handler.cc b/chrome/browser/chromeos/gdata/gdata_protocol_handler.cc
index 97f16a7..99019c6 100644
--- a/chrome/browser/chromeos/gdata/gdata_protocol_handler.cc
+++ b/chrome/browser/chromeos/gdata/gdata_protocol_handler.cc
@@ -99,36 +99,6 @@ void CancelGDataDownloadOnUIThread(const FilePath& gdata_file_path) {
     file_system->GetOperationRegistry()->CancelForFilePath(gdata_file_path);
 }
 
-// Class delegate to find file by resource id and extract relevant file info.
-class GetFileInfoDelegate : public gdata::FindEntryDelegate {
- public:
-  GetFileInfoDelegate() : initial_file_size_(0) {}
-  virtual ~GetFileInfoDelegate() {}
-
-  const std::string& mime_type() const { return mime_type_; }
-  const std::string& file_name() const { return file_name_; }
-  const FilePath& gdata_file_path() const { return gdata_file_path_; }
-  int64 initial_file_size() const { return initial_file_size_; }
-
- private:
-  // GDataFileSystem::FindEntryDelegate overrides.
-  virtual void OnDone(base::PlatformFileError error,
-                      const FilePath& directory_path,
-                      gdata::GDataEntry* entry) OVERRIDE {
-    if (error == base::PLATFORM_FILE_OK && entry && entry->AsGDataFile()) {
-      mime_type_ = entry->AsGDataFile()->content_mime_type();
-      file_name_ = entry->AsGDataFile()->file_name();
-      gdata_file_path_= entry->GetFilePath();
-      initial_file_size_ = entry->file_info().size;
-    }
-  }
-
-  std::string mime_type_;
-  std::string file_name_;
-  FilePath gdata_file_path_;
-  int64 initial_file_size_;
-};
-
 // GDataURLRequesetJob is the gateway between network-level drive://...
 // requests for gdata resources and GDataFileSytem.  It exposes content URLs
 // formatted as drive://<resource-id>.
@@ -355,9 +325,12 @@ bool GDataURLRequestJob::GetMimeType(std::string* mime_type) const {
     return false;
   }
 
-  GetFileInfoDelegate delegate;
-  file_system_->FindEntryByResourceIdSync(resource_id, &delegate);
-  mime_type->assign(delegate.mime_type());
+  GDataEntry* entry = NULL;
+  file_system_->FindEntryByResourceIdSync(
+      resource_id, base::Bind(&ReadOnlyFindEntryCallback, &entry));
+  if (!entry || !entry->AsGDataFile())
+    return false;
+  mime_type->assign(entry->AsGDataFile()->content_mime_type());
   return !mime_type->empty();
 }
 
@@ -507,12 +480,18 @@ void GDataURLRequestJob::StartAsync(GDataFileSystem** file_system) {
   }
 
   // First, check if file metadata is matching our expectations.
-  GetFileInfoDelegate delegate;
-  file_system_->FindEntryByResourceIdSync(resource_id, &delegate);
-
-  mime_type_ = delegate.mime_type();
-  gdata_file_path_ = delegate.gdata_file_path();
-  initial_file_size_ = delegate.initial_file_size();
+  GDataEntry* entry = NULL;
+  file_system_->FindEntryByResourceIdSync(
+      resource_id, base::Bind(&ReadOnlyFindEntryCallback, &entry));
+  if (entry && entry->AsGDataFile()) {
+    mime_type_ = entry->AsGDataFile()->content_mime_type();
+    gdata_file_path_ = entry->GetFilePath();
+    initial_file_size_ = entry->file_info().size;
+  } else {
+    mime_type_.clear();
+    gdata_file_path_.clear();
+    initial_file_size_ = 0;
+  }
   remaining_bytes_ = initial_file_size_;
 
   DVLOG(1) << "Getting file for resource id";
diff --git a/chrome/browser/chromeos/gdata/gdata_util.cc b/chrome/browser/chromeos/gdata/gdata_util.cc
index d06b14e..7b755b3 100644
--- a/chrome/browser/chromeos/gdata/gdata_util.cc
+++ b/chrome/browser/chromeos/gdata/gdata_util.cc
@@ -56,25 +56,6 @@ const int kReadOnlyFilePermissions = base::PLATFORM_FILE_OPEN |
                                      base::PLATFORM_FILE_EXCLUSIVE_READ |
                                      base::PLATFORM_FILE_ASYNC;
 
-class GetFileNameDelegate : public FindEntryDelegate {
- public:
-  GetFileNameDelegate() {}
-  virtual ~GetFileNameDelegate() {}
-
-  const std::string& file_name() const { return file_name_; }
- private:
-  // GDataFileSystem::FindEntryDelegate overrides.
-  virtual void OnDone(base::PlatformFileError error,
-                      const FilePath& directory_path,
-                      GDataEntry* entry) OVERRIDE {
-    if (error == base::PLATFORM_FILE_OK && entry && entry->AsGDataFile()) {
-      file_name_ = entry->AsGDataFile()->file_name();
-    }
-  }
-
-  std::string file_name_;
-};
-
 GDataFileSystem* GetGDataFileSystem(Profile* profile) {
   GDataSystemService* system_service =
       GDataSystemServiceFactory::GetForProfile(profile);
@@ -167,9 +148,15 @@ void ModifyGDataFileResourceUrl(Profile* profile,
           GDataRootDirectory::CACHE_TYPE_TMP).IsParent(gdata_cache_path)) {
     const std::string resource_id =
         gdata_cache_path.BaseName().RemoveExtension().AsUTF8Unsafe();
-    GetFileNameDelegate delegate;
-    file_system->FindEntryByResourceIdSync(resource_id, &delegate);
-    *url = gdata::util::GetFileResourceUrl(resource_id, delegate.file_name());
+    GDataEntry* entry = NULL;
+    file_system->FindEntryByResourceIdSync(
+        resource_id, base::Bind(&ReadOnlyFindEntryCallback, &entry));
+
+    std::string file_name;
+    if (entry && entry->AsGDataFile())
+      file_name = entry->AsGDataFile()->file_name();
+
+    *url = gdata::util::GetFileResourceUrl(resource_id, file_name);
     DVLOG(1) << "ModifyGDataFileResourceUrl " << *url;
   }
 }
diff --git a/chrome/browser/chromeos/gdata/mock_gdata_file_system.h b/chrome/browser/chromeos/gdata/mock_gdata_file_system.h
index abcbb36..d52845d 100644
--- a/chrome/browser/chromeos/gdata/mock_gdata_file_system.h
+++ b/chrome/browser/chromeos/gdata/mock_gdata_file_system.h
@@ -25,8 +25,9 @@ class MockGDataFileSystem : public GDataFileSystemInterface {
   MOCK_METHOD0(StopUpdates, void());
   MOCK_METHOD0(CheckForUpdates, void());
   MOCK_METHOD1(Authenticate, void(const AuthStatusCallback& callback));
-  MOCK_METHOD2(FindEntryByResourceIdSync, void(const std::string& resource_id,
-                                               FindEntryDelegate* delegate));
+  MOCK_METHOD2(FindEntryByResourceIdSync,
+               void(const std::string& resource_id,
+                    const FindEntryCallback& callback));
   MOCK_METHOD2(SearchAsync, void(const std::string& search_query,
                                 const ReadDirectoryCallback& callback));
   MOCK_METHOD3(TransferFileFromRemoteToLocal,
diff --git a/chrome/chrome_browser.gypi b/chrome/chrome_browser.gypi
index ac56455..40ecf54 100644
--- a/chrome/chrome_browser.gypi
+++ b/chrome/chrome_browser.gypi
@@ -509,8 +509,8 @@
         'browser/chromeos/external_protocol_dialog.h',
         'browser/chromeos/gdata/drive_webapps_registry.cc',
         'browser/chromeos/gdata/drive_webapps_registry.h',
-        'browser/chromeos/gdata/find_entry_delegate.cc',
-        'browser/chromeos/gdata/find_entry_delegate.h',
+        'browser/chromeos/gdata/find_entry_callback.cc',
+        'browser/chromeos/gdata/find_entry_callback.h',
         'browser/chromeos/gdata/gdata_auth_service.cc',
         'browser/chromeos/gdata/gdata_auth_service.h',
         'browser/chromeos/gdata/gdata_db.h',