128669 - sidebar panels should use <browser> not <iframe> r=sgehani sr=ben a=brendan

suite/common/sidebar/sidebarOverlay.xul

@@ -150,9 +150,9 @@
                   </hbox>
                   <spacer flex="100%"/>
                 </vbox>
-                <browser class="iframe-panel" flex="1*" src="about:blank"
+                <browser flex="1*" src="about:blank"
                   hidden="true" collapsed="true" content="?content"/>
-                <browser class="iframe-panel" flex="1*" src="about:blank"
+                <browser flex="1*" src="about:blank"
                   hidden="true" collapsed="true" content="?content" type="content" context="contentAreaContextMenu"/>
               </vbox>
             </action>