[Retry] SyncFS: Support resolveLocalFileSystemURL on SyncFileSystem

Original review: https://codereview.chromium.org/23856002/

window.resolveLocalFileSystemURL is originally defined only for FileSystem API,
but it'd be nice if it works on SyncFileSystem in a similar way. For that this
change adds new IPC messages and interfaces.

Blink side change depends on this:
https://codereview.chromium.org/23537011/


BUG=177137,294502
TEST=manual (Get FileSystemURL for a file on SyncFS, and then resolve it)
TEST=unit_tests
TEST=run_webkit_tests.sh http/tests/filesystem/\*
TEST=run_webkit_tests.sh http/tests/inspector/filesystem/\*
TBR=tsepez@chromium.org
NOTRY=true

Review URL: https://chromiumcodereview.appspot.com/23526076

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@224542 0039d316-1c4b-4281-b951-d872f2087c98

17 files changed, 306 insertions, 53 deletions

diff --git a/chrome/browser/sync_file_system/local/local_file_sync_context.cc b/chrome/browser/sync_file_system/local/local_file_sync_context.cc
index 8e45cf2..b4f3a03 100644
--- a/chrome/browser/sync_file_system/local/local_file_sync_context.cc
+++ b/chrome/browser/sync_file_system/local/local_file_sync_context.cc
@@ -507,8 +507,6 @@ void LocalFileSyncContext::InitializeFileSystemContextOnIOThread(
       SyncFileSystemBackend::GetBackend(file_system_context);
   DCHECK(backend);
   if (!backend->change_tracker()) {
-    // First registers the service name.
-    RegisterSyncableFileSystem();
     // Create and initialize LocalFileChangeTracker and call back this method
     // later again.
     std::set<GURL>* origins_with_changes = new std::set<GURL>;
diff --git a/chrome/browser/sync_file_system/local/sync_file_system_backend.cc b/chrome/browser/sync_file_system/local/sync_file_system_backend.cc
index 1c9eef5..199c233 100644
--- a/chrome/browser/sync_file_system/local/sync_file_system_backend.cc
+++ b/chrome/browser/sync_file_system/local/sync_file_system_backend.cc
@@ -66,9 +66,15 @@ SyncFileSystemBackend::SyncFileSystemBackend(Profile* profile)
   DCHECK(CalledOnUIThread());
   if (profile)
     profile_holder_.reset(new ProfileHolder(profile));
+
+  // Register the service name here to enable to crack an URL on SyncFileSystem
+  // even if SyncFileSystemService has not started yet.
+  RegisterSyncableFileSystem();
 }
 
 SyncFileSystemBackend::~SyncFileSystemBackend() {
+  RevokeSyncableFileSystem();
+
   if (change_tracker_) {
     GetDelegate()->file_task_runner()->DeleteSoon(
         FROM_HERE, change_tracker_.release());
diff --git a/chrome/browser/sync_file_system/sync_file_system_service_factory.cc b/chrome/browser/sync_file_system/sync_file_system_service_factory.cc
index 2adb67c..a49355a 100644
--- a/chrome/browser/sync_file_system/sync_file_system_service_factory.cc
+++ b/chrome/browser/sync_file_system/sync_file_system_service_factory.cc
@@ -71,8 +71,6 @@ SyncFileSystemServiceFactory::BuildServiceInstanceFor(
     remote_file_service = mock_remote_file_service_.Pass();
   } else if (CommandLine::ForCurrentProcess()->HasSwitch(
       kEnableSyncFileSystemV2)) {
-    RegisterSyncableFileSystem();
-
     GURL base_drive_url(
         google_apis::DriveApiUrlGenerator::kBaseUrlForProduction);
     GURL base_download_url(
@@ -114,9 +112,6 @@ SyncFileSystemServiceFactory::BuildServiceInstanceFor(
     sync_engine->Initialize();
     remote_file_service = sync_engine.PassAs<RemoteFileSyncService>();
   } else {
-    // FileSystem needs to be registered before DriveFileSyncService runs
-    // its initialization code.
-    RegisterSyncableFileSystem();
     remote_file_service =
         DriveFileSyncService::Create(profile).PassAs<RemoteFileSyncService>();
   }
diff --git a/chrome/browser/sync_file_system/syncable_file_system_util_unittest.cc b/chrome/browser/sync_file_system/syncable_file_system_util_unittest.cc
index b3804b4..31bc00d 100644
--- a/chrome/browser/sync_file_system/syncable_file_system_util_unittest.cc
+++ b/chrome/browser/sync_file_system/syncable_file_system_util_unittest.cc
@@ -112,44 +112,6 @@ TEST(SyncableFileSystemUtilTest,
   RevokeSyncableFileSystem();
 }
 
-TEST(SyncableFileSystemUtilTest, SerializeBeforeOpenFileSystem) {
-  ScopedEnableSyncFSDirectoryOperation enable_directory_operation_;
-  const std::string serialized = kSyncableFileSystemRootURI +
-      CreateNormalizedFilePath(kPath).AsUTF8Unsafe();
-  FileSystemURL deserialized;
-  base::MessageLoop message_loop;
-
-  // Setting up a full syncable filesystem environment.
-  CannedSyncableFileSystem file_system(GURL(kOrigin),
-                                       base::MessageLoopProxy::current().get(),
-                                       base::MessageLoopProxy::current().get());
-  file_system.SetUp();
-  scoped_refptr<LocalFileSyncContext> sync_context =
-      new LocalFileSyncContext(base::FilePath(),
-                               base::MessageLoopProxy::current().get(),
-                               base::MessageLoopProxy::current().get());
-
-  // Before calling initialization we would not be able to get a valid
-  // deserialized URL.
-  EXPECT_FALSE(DeserializeSyncableFileSystemURL(serialized, &deserialized));
-  EXPECT_FALSE(deserialized.is_valid());
-
-  ASSERT_EQ(sync_file_system::SYNC_STATUS_OK,
-            file_system.MaybeInitializeFileSystemContext(sync_context.get()));
-
-  // After initialization this should be ok (even before opening the file
-  // system).
-  EXPECT_TRUE(DeserializeSyncableFileSystemURL(serialized, &deserialized));
-  EXPECT_TRUE(deserialized.is_valid());
-
-  // Shutting down.
-  file_system.TearDown();
-  RevokeSyncableFileSystem();
-  sync_context->ShutdownOnUIThread();
-  sync_context = NULL;
-  base::MessageLoop::current()->RunUntilIdle();
-}
-
 TEST(SyncableFileSystemUtilTest, SyncableFileSystemURL_IsParent) {
   RegisterSyncableFileSystem();
 
diff --git a/content/browser/fileapi/fileapi_message_filter.cc b/content/browser/fileapi/fileapi_message_filter.cc
index ef5f248..1a79ea2 100644
--- a/content/browser/fileapi/fileapi_message_filter.cc
+++ b/content/browser/fileapi/fileapi_message_filter.cc
@@ -38,6 +38,7 @@
 #include "webkit/common/blob/blob_data.h"
 #include "webkit/common/blob/shareable_file_reference.h"
 #include "webkit/common/fileapi/directory_entry.h"
+#include "webkit/common/fileapi/file_system_info.h"
 #include "webkit/common/fileapi/file_system_types.h"
 #include "webkit/common/fileapi/file_system_util.h"
 
@@ -168,6 +169,7 @@ bool FileAPIMessageFilter::OnMessageReceived(
   bool handled = true;
   IPC_BEGIN_MESSAGE_MAP_EX(FileAPIMessageFilter, message, *message_was_ok)
     IPC_MESSAGE_HANDLER(FileSystemHostMsg_Open, OnOpen)
+    IPC_MESSAGE_HANDLER(FileSystemHostMsg_ResolveURL, OnResolveURL)
     IPC_MESSAGE_HANDLER(FileSystemHostMsg_DeleteFileSystem, OnDeleteFileSystem)
     IPC_MESSAGE_HANDLER(FileSystemHostMsg_Move, OnMove)
     IPC_MESSAGE_HANDLER(FileSystemHostMsg_Copy, OnCopy)
@@ -250,6 +252,23 @@ void FileAPIMessageFilter::OnOpen(
       &FileAPIMessageFilter::DidOpenFileSystem, this, request_id));
 }
 
+void FileAPIMessageFilter::OnResolveURL(
+    int request_id,
+    const GURL& filesystem_url) {
+  DCHECK(BrowserThread::CurrentlyOn(BrowserThread::IO));
+  FileSystemURL url(context_->CrackURL(filesystem_url));
+  if (!ValidateFileSystemURL(request_id, url))
+    return;
+  if (!security_policy_->CanReadFileSystemFile(process_id_, url)) {
+    Send(new FileSystemMsg_DidFail(request_id,
+                                   base::PLATFORM_FILE_ERROR_SECURITY));
+    return;
+  }
+
+  context_->ResolveURL(url, base::Bind(
+      &FileAPIMessageFilter::DidResolveURL, this, request_id));
+}
+
 void FileAPIMessageFilter::OnDeleteFileSystem(
     int request_id,
     const GURL& origin_url,
@@ -873,18 +892,35 @@ void FileAPIMessageFilter::DidWrite(int request_id,
 
 void FileAPIMessageFilter::DidOpenFileSystem(int request_id,
                                              base::PlatformFileError result,
-                                             const std::string& name,
+                                             const std::string& filesystem_name,
                                              const GURL& root) {
   DCHECK(BrowserThread::CurrentlyOn(BrowserThread::IO));
   if (result == base::PLATFORM_FILE_OK) {
     DCHECK(root.is_valid());
-    Send(new FileSystemMsg_DidOpenFileSystem(request_id, name, root));
+    Send(new FileSystemMsg_DidOpenFileSystem(
+        request_id, filesystem_name, root));
   } else {
     Send(new FileSystemMsg_DidFail(request_id, result));
   }
   // For OpenFileSystem we do not create a new operation, so no unregister here.
 }
 
+void FileAPIMessageFilter::DidResolveURL(int request_id,
+                                         base::PlatformFileError result,
+                                         const fileapi::FileSystemInfo& info,
+                                         const base::FilePath& file_path,
+                                         bool is_directory) {
+  DCHECK(BrowserThread::CurrentlyOn(BrowserThread::IO));
+  if (result == base::PLATFORM_FILE_OK) {
+    DCHECK(info.root_url.is_valid());
+    Send(new FileSystemMsg_DidResolveURL(
+        request_id, info, file_path, is_directory));
+  } else {
+    Send(new FileSystemMsg_DidFail(request_id, result));
+  }
+  // For ResolveURL we do not create a new operation, so no unregister here.
+}
+
 void FileAPIMessageFilter::DidDeleteFileSystem(
     int request_id,
     base::PlatformFileError result) {
diff --git a/content/browser/fileapi/fileapi_message_filter.h b/content/browser/fileapi/fileapi_message_filter.h
index d1d7373..e9a707f 100644
--- a/content/browser/fileapi/fileapi_message_filter.h
+++ b/content/browser/fileapi/fileapi_message_filter.h
@@ -37,6 +37,7 @@ class FileSystemURL;
 class FileSystemContext;
 class FileSystemOperationRunner;
 struct DirectoryEntry;
+struct FileSystemInfo;
 }
 
 namespace net {
@@ -93,6 +94,8 @@ class CONTENT_EXPORT FileAPIMessageFilter : public BrowserMessageFilter {
               fileapi::FileSystemType type,
               int64 requested_size,
               bool create);
+  void OnResolveURL(int request_id,
+                    const GURL& filesystem_url);
   void OnDeleteFileSystem(int request_id,
                           const GURL& origin_url,
                           fileapi::FileSystemType type);
@@ -201,8 +204,13 @@ class CONTENT_EXPORT FileAPIMessageFilter : public BrowserMessageFilter {
                 bool complete);
   void DidOpenFileSystem(int request_id,
                          base::PlatformFileError result,
-                         const std::string& name,
+                         const std::string& filesystem_name,
                          const GURL& root);
+  void DidResolveURL(int request_id,
+                     base::PlatformFileError result,
+                     const fileapi::FileSystemInfo& info,
+                     const base::FilePath& file_path,
+                     bool is_directory);
   void DidDeleteFileSystem(int request_id,
                            base::PlatformFileError result);
   void DidCreateSnapshot(
diff --git a/content/child/fileapi/file_system_dispatcher.cc b/content/child/fileapi/file_system_dispatcher.cc
index c564f8d..fa73ad1 100644
--- a/content/child/fileapi/file_system_dispatcher.cc
+++ b/content/child/fileapi/file_system_dispatcher.cc
@@ -10,6 +10,7 @@
 #include "base/process/process.h"
 #include "content/child/child_thread.h"
 #include "content/common/fileapi/file_system_messages.h"
+#include "webkit/common/fileapi/file_system_info.h"
 
 namespace content {
 
@@ -20,6 +21,7 @@ class FileSystemDispatcher::CallbackDispatcher {
   typedef FileSystemDispatcher::MetadataCallback MetadataCallback;
   typedef FileSystemDispatcher::ReadDirectoryCallback ReadDirectoryCallback;
   typedef FileSystemDispatcher::OpenFileSystemCallback OpenFileSystemCallback;
+  typedef FileSystemDispatcher::ResolveURLCallback ResolveURLCallback;
   typedef FileSystemDispatcher::WriteCallback WriteCallback;
   typedef FileSystemDispatcher::OpenFileCallback OpenFileCallback;
 
@@ -57,6 +59,13 @@ class FileSystemDispatcher::CallbackDispatcher {
     dispatcher->error_callback_ = error_callback;
     return dispatcher;
   }
+  static CallbackDispatcher* Create(const ResolveURLCallback& callback,
+                                    const StatusCallback& error_callback) {
+    CallbackDispatcher* dispatcher = new CallbackDispatcher;
+    dispatcher->resolve_callback_ = callback;
+    dispatcher->error_callback_ = error_callback;
+    return dispatcher;
+  }
   static CallbackDispatcher* Create(const WriteCallback& callback,
                                     const StatusCallback& error_callback) {
     CallbackDispatcher* dispatcher = new CallbackDispatcher;
@@ -105,6 +114,12 @@ class FileSystemDispatcher::CallbackDispatcher {
     filesystem_callback_.Run(name, root);
   }
 
+  void DidResolveURL(const fileapi::FileSystemInfo& info,
+                     const base::FilePath& file_path,
+                     bool is_directory) {
+    resolve_callback_.Run(info, file_path, is_directory);
+  }
+
   void DidWrite(int64 bytes, bool complete) {
     write_callback_.Run(bytes, complete);
   }
@@ -123,6 +138,7 @@ class FileSystemDispatcher::CallbackDispatcher {
   CreateSnapshotFileCallback snapshot_callback_;
   ReadDirectoryCallback directory_callback_;
   OpenFileSystemCallback filesystem_callback_;
+  ResolveURLCallback resolve_callback_;
   WriteCallback write_callback_;
   OpenFileCallback open_callback_;
 
@@ -150,6 +166,7 @@ bool FileSystemDispatcher::OnMessageReceived(const IPC::Message& msg) {
   bool handled = true;
   IPC_BEGIN_MESSAGE_MAP(FileSystemDispatcher, msg)
     IPC_MESSAGE_HANDLER(FileSystemMsg_DidOpenFileSystem, OnDidOpenFileSystem)
+    IPC_MESSAGE_HANDLER(FileSystemMsg_DidResolveURL, OnDidResolveURL)
     IPC_MESSAGE_HANDLER(FileSystemMsg_DidSucceed, OnDidSucceed)
     IPC_MESSAGE_HANDLER(FileSystemMsg_DidReadDirectory, OnDidReadDirectory)
     IPC_MESSAGE_HANDLER(FileSystemMsg_DidReadMetadata, OnDidReadMetadata)
@@ -174,6 +191,16 @@ void FileSystemDispatcher::OpenFileSystem(
           request_id, origin_url, type, size, create));
 }
 
+void FileSystemDispatcher::ResolveURL(
+    const GURL& filesystem_url,
+    const ResolveURLCallback& success_callback,
+    const StatusCallback& error_callback) {
+  int request_id = dispatchers_.Add(
+      CallbackDispatcher::Create(success_callback, error_callback));
+  ChildThread::current()->Send(new FileSystemHostMsg_ResolveURL(
+          request_id, filesystem_url));
+}
+
 void FileSystemDispatcher::DeleteFileSystem(
     const GURL& origin_url,
     fileapi::FileSystemType type,
@@ -362,6 +389,17 @@ void FileSystemDispatcher::OnDidOpenFileSystem(int request_id,
   dispatchers_.Remove(request_id);
 }
 
+void FileSystemDispatcher::OnDidResolveURL(int request_id,
+                                           const fileapi::FileSystemInfo& info,
+                                           const base::FilePath& file_path,
+                                           bool is_directory) {
+  DCHECK(info.root_url.is_valid());
+  CallbackDispatcher* dispatcher = dispatchers_.Lookup(request_id);
+  DCHECK(dispatcher);
+  dispatcher->DidResolveURL(info, file_path, is_directory);
+  dispatchers_.Remove(request_id);
+}
+
 void FileSystemDispatcher::OnDidSucceed(int request_id) {
   CallbackDispatcher* dispatcher = dispatchers_.Lookup(request_id);
   DCHECK(dispatcher);
diff --git a/content/child/fileapi/file_system_dispatcher.h b/content/child/fileapi/file_system_dispatcher.h
index f3957c3..72ecee6 100644
--- a/content/child/fileapi/file_system_dispatcher.h
+++ b/content/child/fileapi/file_system_dispatcher.h
@@ -24,6 +24,7 @@ struct PlatformFileInfo;
 
 namespace fileapi {
 struct DirectoryEntry;
+struct FileSystemInfo;
 }
 
 class GURL;
@@ -49,6 +50,10 @@ class FileSystemDispatcher : public IPC::Listener {
       const std::string& name,
       const GURL& root)> OpenFileSystemCallback;
   typedef base::Callback<void(
+      const fileapi::FileSystemInfo& info,
+      const base::FilePath& file_path,
+      bool is_directory)> ResolveURLCallback;
+  typedef base::Callback<void(
       int64 bytes,
       bool complete)> WriteCallback;
   typedef base::Callback<void(
@@ -68,6 +73,9 @@ class FileSystemDispatcher : public IPC::Listener {
                       bool create,
                       const OpenFileSystemCallback& success_callback,
                       const StatusCallback& error_callback);
+  void ResolveURL(const GURL& filesystem_url,
+                  const ResolveURLCallback& success_callback,
+                  const StatusCallback& error_callback);
   void DeleteFileSystem(const GURL& origin_url,
                         fileapi::FileSystemType type,
                         const StatusCallback& callback);
@@ -144,6 +152,10 @@ class FileSystemDispatcher : public IPC::Listener {
   void OnDidOpenFileSystem(int request_id,
                            const std::string& name,
                            const GURL& root);
+  void OnDidResolveURL(int request_id,
+                       const fileapi::FileSystemInfo& info,
+                       const base::FilePath& file_path,
+                       bool is_directory);
   void OnDidSucceed(int request_id);
   void OnDidReadMetadata(int request_id,
                          const base::PlatformFileInfo& file_info);
diff --git a/content/child/fileapi/webfilesystem_impl.cc b/content/child/fileapi/webfilesystem_impl.cc
index ac91214..ae3be406 100644
--- a/content/child/fileapi/webfilesystem_impl.cc
+++ b/content/child/fileapi/webfilesystem_impl.cc
@@ -154,6 +154,21 @@ void OpenFileSystemCallbackAdapter(
       MakeTuple(UTF8ToUTF16(name), root));
 }
 
+void ResolveURLCallbackAdapter(
+    int thread_id, int callbacks_id,
+    WaitableCallbackResults* waitable_results,
+    const fileapi::FileSystemInfo& info,
+    const base::FilePath& file_path, bool is_directory) {
+  base::FilePath normalized_path(
+      fileapi::VirtualPath::GetNormalizedFilePath(file_path));
+  CallbackFileSystemCallbacks(
+      thread_id, callbacks_id, waitable_results,
+      &WebFileSystemCallbacks::didResolveURL,
+      MakeTuple(UTF8ToUTF16(info.name), info.root_url,
+                static_cast<WebKit::WebFileSystemType>(info.mount_type),
+                normalized_path.AsUTF16Unsafe(), is_directory));
+}
+
 void StatusCallbackAdapter(int thread_id, int callbacks_id,
                            WaitableCallbackResults* waitable_results,
                            base::PlatformFileError error) {
@@ -332,6 +347,25 @@ void WebFileSystemImpl::openFileSystem(
       make_scoped_ptr(waitable_results));
 }
 
+void WebFileSystemImpl::resolveURL(
+    const WebKit::WebURL& filesystem_url,
+    WebFileSystemCallbacks callbacks) {
+  int callbacks_id = RegisterCallbacks(callbacks);
+  WaitableCallbackResults* waitable_results =
+      WaitableCallbackResults::MaybeCreate(callbacks);
+  CallDispatcherOnMainThread(
+      main_thread_loop_.get(),
+      &FileSystemDispatcher::ResolveURL,
+      MakeTuple(GURL(filesystem_url),
+                base::Bind(&ResolveURLCallbackAdapter,
+                           CurrentWorkerId(), callbacks_id,
+                           base::Unretained(waitable_results)),
+                base::Bind(&StatusCallbackAdapter,
+                           CurrentWorkerId(), callbacks_id,
+                           base::Unretained(waitable_results))),
+      make_scoped_ptr(waitable_results));
+}
+
 void WebFileSystemImpl::deleteFileSystem(
     const WebKit::WebURL& storage_partition,
     WebKit::WebFileSystemType type,
@@ -481,7 +515,7 @@ void WebFileSystemImpl::fileExists(
       MakeTuple(GURL(path), false /* directory */,
                 base::Bind(&StatusCallbackAdapter,
                            CurrentWorkerId(), callbacks_id,
-base::Unretained(waitable_results))),
+                           base::Unretained(waitable_results))),
       make_scoped_ptr(waitable_results));
 }
 
diff --git a/content/child/fileapi/webfilesystem_impl.h b/content/child/fileapi/webfilesystem_impl.h
index 7550545..8f390ff 100644
--- a/content/child/fileapi/webfilesystem_impl.h
+++ b/content/child/fileapi/webfilesystem_impl.h
@@ -54,6 +54,9 @@ class WebFileSystemImpl
       const WebKit::WebFileSystemType type,
       bool create,
       WebKit::WebFileSystemCallbacks);
+  virtual void resolveURL(
+      const WebKit::WebURL& filesystem_url,
+      WebKit::WebFileSystemCallbacks) OVERRIDE;
   virtual void deleteFileSystem(
       const WebKit::WebURL& storage_partition,
       const WebKit::WebFileSystemType type,
diff --git a/content/common/fileapi/file_system_messages.h b/content/common/fileapi/file_system_messages.h
index e277e33..191bf9d 100644
--- a/content/common/fileapi/file_system_messages.h
+++ b/content/common/fileapi/file_system_messages.h
@@ -9,6 +9,7 @@
 #include "ipc/ipc_platform_file.h"
 #include "url/gurl.h"
 #include "webkit/common/fileapi/directory_entry.h"
+#include "webkit/common/fileapi/file_system_info.h"
 #include "webkit/common/fileapi/file_system_types.h"
 #include "webkit/common/quota/quota_types.h"
 
@@ -21,6 +22,12 @@ IPC_STRUCT_TRAITS_BEGIN(fileapi::DirectoryEntry)
   IPC_STRUCT_TRAITS_MEMBER(is_directory)
 IPC_STRUCT_TRAITS_END()
 
+IPC_STRUCT_TRAITS_BEGIN(fileapi::FileSystemInfo)
+  IPC_STRUCT_TRAITS_MEMBER(name)
+  IPC_STRUCT_TRAITS_MEMBER(root_url)
+  IPC_STRUCT_TRAITS_MEMBER(mount_type)
+IPC_STRUCT_TRAITS_END()
+
 IPC_ENUM_TRAITS(fileapi::FileSystemType)
 IPC_ENUM_TRAITS(quota::QuotaLimitType)
 
@@ -33,6 +40,11 @@ IPC_MESSAGE_CONTROL3(FileSystemMsg_DidOpenFileSystem,
                      GURL /* root_url */)
 
 // WebFileSystem response messages.
+IPC_MESSAGE_CONTROL4(FileSystemMsg_DidResolveURL,
+                     int /* request_id */,
+                     fileapi::FileSystemInfo /* filesystem_info */,
+                     base::FilePath /* file_path */,
+                     bool /* is_directory */)
 IPC_MESSAGE_CONTROL1(FileSystemMsg_DidSucceed,
                      int /* request_id */)
 IPC_MESSAGE_CONTROL2(FileSystemMsg_DidReadMetadata,
@@ -69,6 +81,11 @@ IPC_MESSAGE_CONTROL5(FileSystemHostMsg_Open,
                      int64 /* requested_size */,
                      bool /* create */)
 
+// WevFrameClient::resolveURL() message.
+IPC_MESSAGE_CONTROL2(FileSystemHostMsg_ResolveURL,
+                     int /* request_id */,
+                     GURL /* filesystem_url */)
+
 // WebFrameClient::deleteFileSystem() message.
 IPC_MESSAGE_CONTROL3(FileSystemHostMsg_DeleteFileSystem,
                      int /* request_id */,
diff --git a/webkit/browser/fileapi/file_system_context.cc b/webkit/browser/fileapi/file_system_context.cc
index 26a48d4..0888661 100644
--- a/webkit/browser/fileapi/file_system_context.cc
+++ b/webkit/browser/fileapi/file_system_context.cc
@@ -27,6 +27,7 @@
 #include "webkit/browser/fileapi/test_file_system_backend.h"
 #include "webkit/browser/quota/quota_manager.h"
 #include "webkit/browser/quota/special_storage_policy.h"
+#include "webkit/common/fileapi/file_system_info.h"
 #include "webkit/common/fileapi/file_system_util.h"
 
 using quota::QuotaClient;
@@ -49,6 +50,19 @@ void DidOpenFileSystem(
   callback.Run(error, filesystem_name, filesystem_root);
 }
 
+void DidGetMetadataForResolveURL(
+    const base::FilePath& path,
+    const FileSystemContext::ResolveURLCallback& callback,
+    const FileSystemInfo& info,
+    base::PlatformFileError error,
+    const base::PlatformFileInfo& file_info) {
+  if (error != base::PLATFORM_FILE_OK) {
+    callback.Run(error, FileSystemInfo(), base::FilePath(), false);
+    return;
+  }
+  callback.Run(error, info, path, file_info.is_directory);
+}
+
 }  // namespace
 
 // static
@@ -275,6 +289,26 @@ void FileSystemContext::OpenFileSystem(
                           base::Bind(&DidOpenFileSystem, callback));
 }
 
+void FileSystemContext::ResolveURL(
+    const FileSystemURL& url,
+    const ResolveURLCallback& callback) {
+  DCHECK(io_task_runner_->RunsTasksOnCurrentThread());
+  DCHECK(!callback.is_null());
+
+  FileSystemBackend* backend = GetFileSystemBackend(url.type());
+  if (!backend) {
+    callback.Run(base::PLATFORM_FILE_ERROR_SECURITY,
+                 FileSystemInfo(), base::FilePath(), false);
+    return;
+  }
+
+  backend->OpenFileSystem(
+      url.origin(), url.type(),
+      OPEN_FILE_SYSTEM_FAIL_IF_NONEXISTENT,
+      base::Bind(&FileSystemContext::DidOpenFileSystemForResolveURL,
+                 this, url, callback));
+}
+
 void FileSystemContext::DeleteFileSystem(
     const GURL& origin_url,
     FileSystemType type,
@@ -424,8 +458,7 @@ FileSystemURL FileSystemContext::CrackFileSystemURL(
   return current;
 }
 
-void FileSystemContext::RegisterBackend(
-    FileSystemBackend* backend) {
+void FileSystemContext::RegisterBackend(FileSystemBackend* backend) {
   const FileSystemType mount_types[] = {
     kFileSystemTypeTemporary,
     kFileSystemTypePersistent,
@@ -452,4 +485,35 @@ void FileSystemContext::RegisterBackend(
   }
 }
 
+void FileSystemContext::DidOpenFileSystemForResolveURL(
+    const FileSystemURL& url,
+    const FileSystemContext::ResolveURLCallback& callback,
+    const GURL& filesystem_root,
+    const std::string& filesystem_name,
+    base::PlatformFileError error) {
+  DCHECK(io_task_runner_->RunsTasksOnCurrentThread());
+
+  if (error != base::PLATFORM_FILE_OK) {
+    callback.Run(error, FileSystemInfo(), base::FilePath(), false);
+    return;
+  }
+
+  fileapi::FileSystemInfo info(
+      filesystem_name, filesystem_root, url.mount_type());
+
+  // Extract the virtual path not containing a filesystem type part from |url|.
+  base::FilePath parent =
+      base::FilePath::FromUTF8Unsafe(filesystem_root.path());
+  base::FilePath child = base::FilePath::FromUTF8Unsafe(url.ToGURL().path());
+  base::FilePath path;
+
+  if (parent != child) {
+    bool result = parent.AppendRelativePath(child, &path);
+    DCHECK(result);
+  }
+
+  operation_runner()->GetMetadata(
+      url, base::Bind(&DidGetMetadataForResolveURL, path, callback, info));
+}
+
 }  // namespace fileapi
diff --git a/webkit/browser/fileapi/file_system_context.h b/webkit/browser/fileapi/file_system_context.h
index 9762b68..21a31b8 100644
--- a/webkit/browser/fileapi/file_system_context.h
+++ b/webkit/browser/fileapi/file_system_context.h
@@ -49,8 +49,8 @@ class CopyOrMoveFileValidatorFactory;
 class ExternalFileSystemBackend;
 class ExternalMountPoints;
 class FileStreamWriter;
-class FileSystemFileUtil;
 class FileSystemBackend;
+class FileSystemFileUtil;
 class FileSystemOperation;
 class FileSystemOperationRunner;
 class FileSystemOptions;
@@ -61,6 +61,7 @@ class MountPoints;
 class SandboxFileSystemBackend;
 
 struct DefaultContextDeleter;
+struct FileSystemInfo;
 
 // This class keeps and provides a file system context for FileSystem API.
 // An instance of this class is created and owned by profile.
@@ -154,6 +155,12 @@ class WEBKIT_STORAGE_BROWSER_EXPORT FileSystemContext
                               const std::string& name,
                               const GURL& root)> OpenFileSystemCallback;
 
+  // Used for ResolveURL.
+  typedef base::Callback<void(base::PlatformFileError result,
+                              const FileSystemInfo& info,
+                              const base::FilePath& file_path,
+                              bool is_directory)> ResolveURLCallback;
+
   // Used for DeleteFileSystem.
   typedef base::Callback<void(base::PlatformFileError result)>
       DeleteFileSystemCallback;
@@ -169,8 +176,15 @@ class WEBKIT_STORAGE_BROWSER_EXPORT FileSystemContext
       OpenFileSystemMode mode,
       const OpenFileSystemCallback& callback);
 
+  // Opens the filesystem for the given |url| as read-only, and then checks the
+  // existence of the file entry referred by the URL. This should be called on
+  // the IO thread.
+  void ResolveURL(
+      const FileSystemURL& url,
+      const ResolveURLCallback& callback);
+
   // Deletes the filesystem for the given |origin_url| and |type|. This should
-  // be called on the IO Thread.
+  // be called on the IO thread.
   void DeleteFileSystem(
       const GURL& origin_url,
       FileSystemType type,
@@ -274,6 +288,13 @@ class WEBKIT_STORAGE_BROWSER_EXPORT FileSystemContext
   // the constructor.
   void RegisterBackend(FileSystemBackend* backend);
 
+  void DidOpenFileSystemForResolveURL(
+      const FileSystemURL& url,
+      const ResolveURLCallback& callback,
+      const GURL& filesystem_root,
+      const std::string& filesystem_name,
+      base::PlatformFileError error);
+
   // Returns a FileSystemBackend, used only by test code.
   SandboxFileSystemBackend* sandbox_backend() const {
     return sandbox_backend_.get();
diff --git a/webkit/common/fileapi/file_system_info.cc b/webkit/common/fileapi/file_system_info.cc
new file mode 100644
index 0000000..269c021
--- /dev/null
+++ b/webkit/common/fileapi/file_system_info.cc
@@ -0,0 +1,24 @@
+// Copyright 2013 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 "webkit/common/fileapi/file_system_info.h"
+
+namespace fileapi {
+
+FileSystemInfo::FileSystemInfo()
+    : mount_type(fileapi::kFileSystemTypeTemporary) {
+}
+
+FileSystemInfo::FileSystemInfo(const std::string& name,
+                               const GURL& root_url,
+                               fileapi::FileSystemType mount_type)
+    : name(name),
+      root_url(root_url),
+      mount_type(mount_type) {
+}
+
+FileSystemInfo::~FileSystemInfo() {
+}
+
+}  // namespace fileapi
diff --git a/webkit/common/fileapi/file_system_info.h b/webkit/common/fileapi/file_system_info.h
new file mode 100644
index 0000000..b71739a
--- /dev/null
+++ b/webkit/common/fileapi/file_system_info.h
@@ -0,0 +1,31 @@
+// Copyright 2013 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 WEBKIT_COMMON_FILEAPI_FILE_SYSTEM_INFO_H_
+#define WEBKIT_COMMON_FILEAPI_FILE_SYSTEM_INFO_H_
+
+#include "url/gurl.h"
+#include "webkit/common/fileapi/file_system_types.h"
+#include "webkit/common/webkit_storage_common_export.h"
+
+namespace fileapi {
+
+// This struct is used to send the necessary information for Blink to create a
+// DOMFileSystem.  Since Blink side only uses mount_type (rather than
+// detailed/cracked filesystem type) this only contains mount_type but not type.
+struct WEBKIT_STORAGE_COMMON_EXPORT FileSystemInfo {
+  FileSystemInfo();
+  FileSystemInfo(const std::string& filesystem_name,
+                 const GURL& root_url,
+                 fileapi::FileSystemType mount_type);
+  ~FileSystemInfo();
+
+  std::string name;
+  GURL root_url;
+  fileapi::FileSystemType mount_type;
+};
+
+}  // namespace fileapi
+
+#endif  // WEBKIT_COMMON_FILEAPI_FILE_SYSTEM_INFO_H_
diff --git a/webkit/common/fileapi/file_system_util.cc b/webkit/common/fileapi/file_system_util.cc
index bc9aba7..6229bc2 100644
--- a/webkit/common/fileapi/file_system_util.cc
+++ b/webkit/common/fileapi/file_system_util.cc
@@ -296,6 +296,8 @@ WebKit::WebFileError PlatformFileErrorToWebFileError(
       return WebKit::WebFileErrorSecurity;
     case base::PLATFORM_FILE_ERROR_NO_SPACE:
       return WebKit::WebFileErrorQuotaExceeded;
+    case base::PLATFORM_FILE_ERROR_INVALID_URL:
+      return WebKit::WebFileErrorEncoding;
     default:
       return WebKit::WebFileErrorInvalidModification;
   }
diff --git a/webkit/storage_common.gyp b/webkit/storage_common.gyp
index 01e8f23..a77d4c5 100644
--- a/webkit/storage_common.gyp
+++ b/webkit/storage_common.gyp
@@ -32,6 +32,8 @@
         'common/database/database_identifier.cc',
         'common/fileapi/directory_entry.cc',
         'common/fileapi/directory_entry.h',
+        'common/fileapi/file_system_info.cc',
+        'common/fileapi/file_system_info.h',
         'common/fileapi/file_system_types.h',
         'common/fileapi/file_system_util.cc',
         'common/fileapi/file_system_util.h',