Prepare declarativeContent API for new script injection feature. Added Javascript types and functio…

extensions/common/watched_pages_recipient.h

Index: extensions/common/watched_pages_recipient.h
diff --git a/extensions/common/watched_pages_recipient.h b/extensions/common/watched_pages_recipient.h
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index 0000000000000000000000000000000000000000..dad3e936efe633f985721b8eafa8fedcc23e9697
--- /dev/null
+++ b/extensions/common/watched_pages_recipient.h
@@ -0,0 +1,18 @@
+// 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.
+
+#ifndef EXTENSIONS_COMMON_WATCHED_PAGES_RECIPIENT_H_
+#define EXTENSIONS_COMMON_WATCHED_PAGES_RECIPIENT_H_
+
+namespace extensions {
+
+enum WatchedPagesRecipient {
+  CONTENT_RULES_REGISTRY = 0,

[Jeffrey Yasskin, 2014/06/27 22:03:41]

Definitely comment what these mean. If possible, though, it'd be nice to avoid
the need for this enum.

[Mark Dittmer, 2014/06/30 11:50:35]

We could certainly change this to a boolean, but I feel that there are two
drawbacks to that change:

1. What do we name it? replyToBrowser captures the (non-)IPC'ness of the
behavior, but obscures where the data is sent when there is no IPC.
replyToScriptManagerOrRulesRegistry is already too verbose, and it doesn't even
indicate which is true and which is false. I think your point that comments are
needed here highlights why an enum is probably the right choice.
2. If we switch to a boolean and later end up routing data to a third component,
we'll have to change the type in the message rather than simply augment it.

If by your comment you mean that it would be nice to avoid sometimes sending to
the browser process and sometimes not, I agree. Unfortunately, it doesn't look
like we can achieve this (based on our recent email conversations about timely
browser notification of page loads).

+  USER_SCRIPT_MANAGER,
+  WATCHED_PAGES_RECIPIENT_LAST = USER_SCRIPT_MANAGER,
+};
+
+}
+
+#endif  // EXTENSIONS_COMMON_WATCHED_PAGES_RECIPIENT_H_