Avoid sync IPCs for FileSystem API

chrome/common/render_messages.h

 // 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.
 
 // Multiply-included file, no traditional include guard.
 #include <map>
 #include <set>
 #include <string>
 #include <vector>
 
@@ skipping 350 matching lines @@
 // Sent in response to ViewHostMsg_DidBlockDisplayingInsecureContent.
 IPC_MESSAGE_ROUTED1(ChromeViewMsg_SetAllowDisplayingInsecureContent,
                     bool /* allowed */)
 
 // Sent in response to ViewHostMsg_DidBlockRunningInsecureContent.
 IPC_MESSAGE_ROUTED1(ChromeViewMsg_SetAllowRunningInsecureContent,
                     bool /* allowed */)
 
 IPC_MESSAGE_ROUTED0(ChromeViewMsg_ReloadFrame)
 
+// Tells the renderer whether or not a file system access has been allowed.
+IPC_MESSAGE_ROUTED2(ChromeViewMsg_RequestFileSystemAccessResponse,
+                    int  /* request_id */,
+                    bool /* allowed */)
+
 // Sent when the profile changes the kSafeBrowsingEnabled preference.
 IPC_MESSAGE_ROUTED1(ChromeViewMsg_SetClientSidePhishingDetection,
                     bool /* enable_phishing_detection */)
 
 // Asks the renderer for a thumbnail of the image selected by the most
 // recently opened context menu, if there is one. If the image's area
 // is greater than thumbnail_min_area it will be downscaled to
 // be within thumbnail_max_size. The possibly downsampled image will be
 // returned in a ChromeViewHostMsg_RequestThumbnailForContextNode_ACK message.
 IPC_MESSAGE_ROUTED2(ChromeViewMsg_RequestThumbnailForContextNode,
@@ skipping 103 matching lines @@
                             bool /* allowed */)
 
 // Sent by the renderer process to check whether access to FileSystem is
 // granted by content settings.
 IPC_SYNC_MESSAGE_CONTROL3_1(ChromeViewHostMsg_AllowFileSystem,
                             int /* render_frame_id */,
                             GURL /* origin_url */,
                             GURL /* top origin url */,
                             bool /* allowed */)
 
+// Sent by the renderer process to check whether access to FileSystem is
+// granted by content settings.
+IPC_MESSAGE_ROUTED3(ChromeViewHostMsg_RequestFileSystemAccess,
+                    int /* request_id */,
+                    GURL /* origin_url */,
+                    GURL /* top origin url */)
+
 // Sent by the renderer process to check whether access to Indexed DBis
 // granted by content settings.
 IPC_SYNC_MESSAGE_CONTROL4_1(ChromeViewHostMsg_AllowIndexedDB,
                             int /* render_frame_id */,
                             GURL /* origin_url */,
                             GURL /* top origin url */,
                             base::string16 /* database name */,
                             bool /* allowed */)
 
 // Return information about a plugin for the given URL and MIME type.
@@ skipping 260 matching lines @@
                      std::vector<GURL> /* search_urls */,
                      GURL /* new_tab_page_url */)
 
 // Tells listeners that a detailed message was reported to the console by
 // WebKit.
 IPC_MESSAGE_ROUTED4(ChromeViewHostMsg_DetailedConsoleMessageAdded,
                     base::string16 /* message */,
                     base::string16 /* source */,
                     extensions::StackTrace /* stack trace */,
                     int32 /* severity level */)