A service provided by embedding applications to override
 the default XUL implmementation of XPInstall dialogs.

 Embedding applications which wish to override the default
 XUL dialogs need to create a component which implements
 this interface and registers with the Contract ID
 "@mozilla.org/embedui/xpinstall-dialog-service;1"

 @status UNDER_REVIEW
[scriptable, uuid(8cdd8baa-1dd2-11b2-909a-f0178da5c5ff)]
interface nsIXPIDialogService : nsISupports

Methods

 @brief  Ask the user if it's OK to install

 When called the XPIDialogService implementation should pose an
 install confirmation dialog and return the user's response

 @param parent        a window that can be used to parent the modal dialog

 @param packageList   For each install package there will be three strings,
                      a display name, a source URL, and a the name of the
                      organization that signed this install.  Note that the
                      name of the signer is not verified.  Verification
                      happens when the the install has completely downloaded.
                      Your user interface should only suggest that the 
                      install may be signed by this organization name.
                      Note that an unsigned archive is indicated by an 
                      empty string.   

 @param count         The number of strings in the packageList. This
                      will always be three times the number of 
                      packages.

 @return true to install, false to cancel
boolean confirmInstall(in nsIDOMWindow parent, [array, size_is(count)] in wstring packageList, in unsigned long count) 
 @brief Create and open a download-and-install progress dialog

 When called the XPIDialogService implementation creates and opens
 a dialog to display the status of the install. When the dialog
 is ready to be used then the observer must be called: the subject
 is an nsIXPIProgressDialog that nsXPInstallManager can use to control
 the dialog, the topic is "xpinstall-progress"  and the data is "open".

 If the user wishes to cancel the download, the dialog can call the
 observe method with the same subject and topic and the data "cancel".

 @note Unless this routine throws an exception the observer <b>must</b>
 be called or nsXPInstallManager will wait forever and never clean
 itself up.

 @param packageList   three strings per package as in confirmInstall()
 @param count         the number of strings in the list
 @param observer      nsIObserver to receive messages from the dialog
void openProgressDialog([array, size_is(count)] in wstring packageList, in unsigned long count, in nsIObserver observer)