erp5_document_scanner: simplify code

bt5/erp5_document_scanner/SkinTemplateItem/portal_skins/erp5_document_scanner/Base_getDocumentScannerSelectionName.py

-return "document_scanner_selection_%s" % context.REQUEST["HTTP_USER_AGENT"]
+return "document_scanner_selection"

bt5/erp5_document_scanner/SkinTemplateItem/portal_skins/erp5_document_scanner/Base_getDocumentScannerSelectionName.xml

@@ -50,7 +50,7 @@
         </item>
         <item>
             <key> <string>_params</string> </key>
-            <value> <string>REQUEST</string> </value>
+            <value> <string></string> </value>
         </item>
         <item>
             <key> <string>id</string> </key>

bt5/erp5_document_scanner/SkinTemplateItem/portal_skins/erp5_document_scanner/Base_getPreferredCropperSettingsFromPreference.py

@@ -2,10 +2,11 @@ import json
 
 portal = context.getPortalObject()
 
-canvas_data = portal.portal_selections.getSelectionParamsFor(
-  context.Base_getDocumentScannerSelectionName(context.REQUEST),
+selection_mapping = portal.portal_selections.getSelectionParamsFor(
+  context.Base_getDocumentScannerSelectionName(),
   REQUEST=context.REQUEST) or {}
 
+canvas_data = selection_mapping.get(context.REQUEST["HTTP_USER_AGENT"]) or {}
 canvas_data["dialog_method"] = context.Base_storeDocumentFromCameraInActiveProcess.getId()
 
 return json.dumps(canvas_data)

bt5/erp5_document_scanner/SkinTemplateItem/portal_skins/erp5_document_scanner/Base_storeDocumentFromCameraInActiveProcess.py

@@ -8,9 +8,16 @@ gadget_data = json.loads(document_scanner_gadget)
 image_str = decodestring(gadget_data.pop("input_value"))
 preferred_cropped_canvas_data = gadget_data["preferred_cropped_canvas_data"] or {}
 
+selection_mapping = portal.portal_selections.getSelectionParamsFor(
+  context.Base_getDocumentScannerSelectionName(),
+  REQUEST=context.REQUEST) or {}
+
+http_user_agent = context.REQUEST["HTTP_USER_AGENT"]
+selection_mapping[http_user_agent] = preferred_cropped_canvas_data
+
 portal.portal_selections.setSelectionParamsFor(
-  context.Base_getDocumentScannerSelectionName(context.REQUEST),
-  preferred_cropped_canvas_data,
+  context.Base_getDocumentScannerSelectionName(),
+  selection_mapping,
   context.REQUEST
 )