WebContentsObserver IPC Listener Census

	A	B	C	D	E	F
1	8 April 2014: A census of of classes that override WebContentsObserver::OnMessageRecieved
2	Class	keeps state about remote IPC sender?	Calls WCO::Send asynchronously?	provides privileged (origin restricted) functionality that will be enforced by browser?	operating logically on ...	Fit for FrameMessagePipe?
3	AppWindowContentsImpl	n	n (extensionfndispatcher)	y	webcontents	n
4	ShellAppWindow	n	n (extensionfndispatcher)	y	webcontents	n
5	ContentAutofillDriver	y (AutofillManager)	y	y	frame	y
6	AshKeyboardControllerProxy	n	n (extensionfndispatcher)	n	?	n
7	AshPanelContents	n	n (extensionfndispatcher)	n	webcontents	n
8	BalloonHost	don't care	don't care	don't care	don't care	n/a
9	ChromePasswordManagerClient	y (ContentPasswordManagerDriver)	y	y	frame	y
10	CoreTabHelper	n	n	n	browser on behalf of webcontents	n
11	InfoBarService	n	n (uses SendToAllFrames)	n	page	n
12	MalwareDetails	y (I think? e.g. cache_collector_ / redirects_collector_)	n (will probably use SendToAllFrames to effect collection)	n	?	maybe
13	PDFTabHelper	n	y (modal password prompt)	n	frame	y
14	PanelHost	n	n (extensionfndispatcher)	n	webcontents	?
15	PluginObserver					?
16	PluginPermissionHelper	n	n (? OnFindMissingPlugin?)	?		?
17	RequestPrintPreviewObserver (test code)	n	n	n	test	n
18	SearchEngineTabHelper	n	n	sorta	top level frame only	maybe
19	SearchIPCRouter					?
20	TabSpecificContentSettings	y	n	y (but unrelated)	WebContents (I think?)	?
21	TranslateTabHelper	n	y	n	page or top level frame	maybe
22	UIThreadExtensionFunction::RenderHostTracker	maybe (depends on delegate)	y, but RFH specific	y	frame. Is RFH aware today, and essentially this class rolls its own RFHO. current implementation ought to be updated to not accept messages from frames other than the tracked one.	y
23	BrowserPluginEmbedder	n	n	y		?
24	BrowserPluginGuest					?
25	DevToolsFrontendHost					?
26	InterstitialPageImpl					?
27	browser_plugin_host_browsertest.cc!MessageObserver				test	n
28	NotifyDoneForwarder				webcontents	n
29	OverscrollNavigationOverlay					?
30	SavePackage	y (finished_ / wait_state_)	will need to send to N frames and wait for N responses	n	frames on behalf of page	y
31	WebKitTestController				stdout / file system / browser	maybe
32	script_executor.cc!Handler				frame, but short lived (might not fit FrameMessagePipe model)	maybe - might be a bad fit
33	ChromeExtensionWebContentsObserver	n	n	y		?
34	ExtensionHost	n	n	y	webcontents (if we care about unprivileged iframes within extensionhost webcontents, then this will have to be hardened)	n
35	TabHelper	n	y	y	frame.	y
36	PrerenderContents	n	n	n	webcontents	n
37	PrintPreviewMessageHandler	n	n	n	webcontents	n
38	PrintViewManager	y (scripted_print_preview_rph_)	y	?	webcontents?	n
39	PrintViewManagerBase	y (cookie_)	n	?	webcontents?	n
40	ClientSideDetectionHost	n	n	n	webcontents, probably (unclear how this will work with oopif)	maybe
41	BrowserMediaPlayerManager	y	y	?	frame.	y
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