Forward MIME types to BrowserPlugin when a viewer is specified.

chrome/common/extensions/api/streams_private.idl

Index: chrome/common/extensions/api/streams_private.idl
diff --git a/chrome/common/extensions/api/streams_private.idl b/chrome/common/extensions/api/streams_private.idl
index 2d3badaa9a225760c474a66f5148ae817ce18ced..3b8942ea71013a163b031e0f90279397114ebe48 100644
--- a/chrome/common/extensions/api/streams_private.idl
+++ b/chrome/common/extensions/api/streams_private.idl
@@ -18,6 +18,10 @@ namespace streamsPrivate {
     // a tab, it will be -1.
     long tabId;
 
+    // The ID of the view that will render the stream, if the viewer was opened
+    // in a plugin.
+    DOMString? viewId;
+
     // The amount of data the Stream should contain, if known.  If there is no
     // information on the size it will be -1.
     long expectedContentSize;