Add platformBrowserBindings for cut/copy/paste on MacOS and Windows to fix PDT+ bug 28680. r=pinkerton, a=jar

xpfe/global/resources/content/mac/platformBrowserBindings.xul

@@ -17,6 +17,18 @@
    onkeypress="
      var controller = document.commandDispatcher.getControllerForCommand('cmd_scrollBottom');
      controller.doCommand('cmd_scrollBottom');"/>
+<key id="macCutKey" key="x" xulkey="true"
+  onkeypress="
+    var controller = document.commandDispatcher.getControllerForCommand('cmd_cut');
+    controller.doCommand('cmd_cut');"/>
+<key id="macCopyKey" key="c" xulkey="true"
+  onkeypress="
+    var controller = document.commandDispatcher.getControllerForCommand('cmd_copy');
+    controller.doCommand('cmd_copy');"/>
+<key id="macPasteKey" key="v" xulkey="true"
+  onkeypress="
+    var controller = document.commandDispatcher.getControllerForCommand('cmd_paste');
+    controller.doCommand('cmd_paste');"/>
 
 </keyset>
 <!-- End Mac-specific key bindings -->

xpfe/global/resources/content/win/platformBrowserBindings.xul

@@ -21,7 +21,19 @@
   onkeypress="
     var controller = document.commandDispatcher.getControllerForCommand('cmd_paste');
     controller.doCommand('cmd_paste');"/>
-
+    
+<key id="winCutKey" key="x" control="true"
+  onkeypress="
+    var controller = document.commandDispatcher.getControllerForCommand('cmd_cut');
+    controller.doCommand('cmd_cut');"/>
+<key id="winCopyKey" key="c" control="true"
+  onkeypress="
+    var controller = document.commandDispatcher.getControllerForCommand('cmd_copy');
+    controller.doCommand('cmd_copy');"/>
+<key id="winPasteKey" key="v" control="true"
+  onkeypress="
+    var controller = document.commandDispatcher.getControllerForCommand('cmd_paste');
+    controller.doCommand('cmd_paste');"/>
 </keyset>
 
 <!-- End Unix-specific keybindings -->