Add Stream support to WebBlobRegistry and FileAPIMessageFilter.

content/common/fileapi/webblob_messages.h

Index: content/common/fileapi/webblob_messages.h
diff --git a/content/common/fileapi/webblob_messages.h b/content/common/fileapi/webblob_messages.h
index daf983707addc996b888b09525565027ff03ba37..2239f453a4b2c5d2995fe6b8ef34941a9390dea8 100644
--- a/content/common/fileapi/webblob_messages.h
+++ b/content/common/fileapi/webblob_messages.h
@@ -17,7 +17,12 @@
 IPC_MESSAGE_CONTROL1(BlobHostMsg_StartBuildingBlob,
                      GURL /* url */)
 
-// Appends data to a blob being built.
+// Registers a stream as being built.
+IPC_MESSAGE_CONTROL2(BlobHostMsg_StartBuildingStream,
+                     GURL /* url */,
+                     std::string /* content_type */)
+
+// Appends data to a blob or stream being built.
 IPC_MESSAGE_CONTROL2(BlobHostMsg_AppendBlobDataItem,
                      GURL /* url */,
                      webkit_blob::BlobData::Item)
@@ -28,17 +33,17 @@ IPC_SYNC_MESSAGE_CONTROL3_0(BlobHostMsg_SyncAppendSharedMemory,
                             base::SharedMemoryHandle,
                             size_t /* buffer size */)
 
-// Finishes building a blob.
+// Finishes building a blob or stream.
 IPC_MESSAGE_CONTROL2(BlobHostMsg_FinishBuildingBlob,
                      GURL /* url */,
                      std::string /* content_type */)
 
-// Creates a new blob that's a clone of an existing src blob.
-// The source blob must be fully built.
+// Creates a new blob (or stream) that's a clone of an existing src blob (or
+// stream). The source blob (or stream) must be fully built.
 IPC_MESSAGE_CONTROL2(BlobHostMsg_CloneBlob,
                      GURL /* url */,
                      GURL /* src_url */)
 
-// Removes a blob.
+// Removes a blob or stream.
 IPC_MESSAGE_CONTROL1(BlobHostMsg_RemoveBlob,
                      GURL /* url */)