FileSystem mods: Changes to snapshot file creation to remove dependencies on blobs.

content/common/fileapi/file_system_messages.h

Index: content/common/fileapi/file_system_messages.h
===================================================================
--- content/common/fileapi/file_system_messages.h	(revision 181828)
+++ content/common/fileapi/file_system_messages.h	(working copy)
@@ -35,6 +35,10 @@
                      int /* request_id */,
                      base::PlatformFileInfo,
                      base::FilePath /* true platform path, where possible */)
+IPC_MESSAGE_CONTROL3(FileSystemMsg_DidCreateSnapshotFile,

[michaeln, 2013/02/14 01:46:27]

@aedla, in some cases where the existing FileSystemMsg_DidReadMetadata is sent
in response to an ipc, we'll send this new more specific message instead... same
payload with a different msgtype to invoke more specific processing on the other
side.

from a security pov, i believe things are identical before and after the change

+                     int /* request_id */,
+                     base::PlatformFileInfo,
+                     base::FilePath /* true platform path */)
 IPC_MESSAGE_CONTROL3(FileSystemMsg_DidReadDirectory,
                      int /* request_id */,
                      std::vector<base::FileUtilProxy::Entry> /* entries */,
@@ -143,12 +147,23 @@
 IPC_MESSAGE_CONTROL1(FileSystemHostMsg_NotifyCloseFile,
                      GURL /* file path */)
 
-// WebFileSystem::createSnapshotFileAndReadMetadata() message.
-IPC_MESSAGE_CONTROL3(FileSystemHostMsg_CreateSnapshotFile,
+// DEPRECATED
+IPC_MESSAGE_CONTROL3(FileSystemHostMsg_CreateSnapshotFile_Deprecated,
                      int /* request_id */,
                      GURL /* blob_url */,
                      GURL /* file_path */)
 
+// WebFileSystem::createSnapshotFileAndReadMetadata() message.
+IPC_MESSAGE_CONTROL2(FileSystemHostMsg_CreateSnapshotFile,
+                     int /* request_id */,
+                     GURL /* file_path */)
+
+// Renderers are expected to send this message after having processed
+// the FileSystemMsg_DidCreateSnapshotFile message. In particular,
+// after having created a BlobDataHandle backed by the snapshot file.
+IPC_MESSAGE_CONTROL1(FileSystemHostMsg_DidReceiveSnapshotFile,
+                     int /* request_id */)
+
 // For Pepper's URL loader.
 IPC_SYNC_MESSAGE_CONTROL1_1(FileSystemHostMsg_SyncGetPlatformPath,
                             GURL /* file path */,