Declarative content scripts: Renderer-side: per-extension shared memory regions (lazily loaded)

extensions/common/extension_messages.h

 // Copyright 2014 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.
 
 // IPC messages for extensions.
 // Multiply-included message file, hence no include guard.
 
 #include <string>
 #include <vector>
 
@@ skipping 363 matching lines @@
                      // extension ids
                      extensions::ExtensionsClient::ScriptingWhitelist)
 
 // Notification that renderer should run some JavaScript code.
 IPC_MESSAGE_ROUTED1(ExtensionMsg_ExecuteCode,
                     ExtensionMsg_ExecuteCode_Params)
 
 // Notification that the user scripts have been updated. It has one
 // SharedMemoryHandle argument consisting of the pickled script data. This
 // handle is valid in the context of the renderer.
+// If |owner| is not empty, then the shared memory handle refers to |owner|'s
+// programmatically defined scripts. Otherwise, the handle refers to all
+// extensions' statically defined scripts.
 // If |changed_extensions| is not empty, only the extensions in that set will
-// be updated. Otherwise, all extensions will be updated.
-IPC_MESSAGE_CONTROL2(ExtensionMsg_UpdateUserScripts,
+// be updated. Otherwise, all extensions that have scripts in the shared memory
+// region will be updated.
+IPC_MESSAGE_CONTROL3(ExtensionMsg_UpdateUserScripts,

[Jeffrey Yasskin, 2014/07/24 21:09:19]

How are you going to use the scripts in the single-extension shared-memory
region that this creates? declarativeContent needs to be able to run particular
scripts on each page, depending on what matches, but I don't see any IDs in this
message. What's the plan?

[Mark Dittmer, 2014/07/25 15:09:05]

Short answer: This data lives in the UserScript objects in the shared memory
region.

Long answer: Ultimately, this data will either: (a) live in the UserScript
object (matches, excludeMatches, etc.) or (b) be absent and the
UserScript::run_at will be something like "BROWSER_DRIVEN" and an IPC from the
browser that has checked rich URL+CSS conditions will send a "fire this script
now" IPC. This CL only contains renderer-side changes for (a).

                      base::SharedMemoryHandle,
+                     extensions::ExtensionId /* owner */,
                      std::set<std::string> /* changed extensions */)
 
 // Tell the render view which browser window it's being attached to.
 IPC_MESSAGE_ROUTED1(ExtensionMsg_UpdateBrowserWindowId,
                     int /* id of browser window */)
 
 // Tell the render view what its tab ID is.
 IPC_MESSAGE_ROUTED1(ExtensionMsg_SetTabId,
                     int /* id of tab */)
 
@@ skipping 279 matching lines @@
 //   FrameHostMsg_DidCommitProvisionalLoad. Currently this only fires for the
 //   main frame.
 // * Something changed on an existing frame causing the set of matching searches
 //   to change.
 IPC_MESSAGE_ROUTED1(ExtensionHostMsg_OnWatchedPageChange,
                     std::vector<std::string> /* Matching CSS selectors */)
 
 // Sent by the renderer when it has received a Blob handle from the browser.
 IPC_MESSAGE_CONTROL1(ExtensionHostMsg_TransferBlobsAck,
                      std::vector<std::string> /* blob_uuids */)