Add a menu option for the right-hand Ctrl -> Meta mapping.

remoting/webapp/crd/js/desktop_connected_view.js

Index: remoting/webapp/crd/js/desktop_connected_view.js
diff --git a/remoting/webapp/crd/js/desktop_connected_view.js b/remoting/webapp/crd/js/desktop_connected_view.js
index 9f7b56ae2c6356eeae78bf9b24a8e69692dcd098..a066284dad75d65eb16e68b3b753f038e5703456 100644
--- a/remoting/webapp/crd/js/desktop_connected_view.js
+++ b/remoting/webapp/crd/js/desktop_connected_view.js
@@ -106,6 +106,15 @@ remoting.DesktopConnectedView.prototype.getResizeToClient = function() {
   return false;
 };
 
+/**
+ * @return {boolean} True if the right-hand Ctrl key should be remapped to the
+ *     Meta (Windows, Command) key.
+ */
+remoting.DesktopConnectedView.prototype.getMapRightCtrl = function() {
+  var currentMapping = this.host_.options.remapKeys;
+  return currentMapping.search('0x0700e4>0x0700e7') !== -1;
+};
+
 remoting.DesktopConnectedView.prototype.toggleStats = function() {
   this.stats_.toggle();
 };
@@ -235,6 +244,29 @@ remoting.DesktopConnectedView.prototype.onFullScreenChanged_ = function (
 };
 
 /**
+ * Set whether or not the right-hand Ctrl key should send the Meta (Windows,
+ * Command) key-code.
+ *
+ * @param {boolean} enable True to enable the mapping; false to disable.
+ */
+remoting.DesktopConnectedView.prototype.setMapRightCtrl = function(enable) {
+  if (enable === this.getMapRightCtrl()) {
+    return;
+  }
+  var currentMapping = this.host_.options.remapKeys;
+  if (enable) {
+    var separator = (currentMapping === '') ? '' : ',';
+    currentMapping += (separator + '0x0700e4>0x0700e7');

[Wez, 2015/06/01 19:47:57]

This code's made complex by the need to support the right-ctrl mapping alongside
custom mappings; do we actually need that, though? Could we just say if you use
custom mappings then they completely override this option? That's pretty much
the way the lower-level setRemapKeys() option works on ChromeOS.

[Jamie, 2015/06/01 19:59:51]

Storing it as a map would make it less complex, so i think that's a better
solution. I'd prefer to keep it generic; the alternative sounds like would
involve more special-case code for a scenario that almost no users will be in.

[Wez, 2015/06/01 20:01:36]

Right - my point is that your current code is coping with a special case
(currentMapping being something other than empty, or the CrOS mapping) that few
users will have - you can pretty much have this function set the mapping
directly, for most users, surely?

[Jamie, 2015/06/01 22:27:02]

I've simplified the implementation as you suggest. A downside is that the menu
item will not necessarily show the right thing if a custom setting is in effect,
and it might be too easy to accidentally hit it, requiring the console command
be re-entered. An alternative would be to hide the option if a non-standard
configuration is in effect, but TBH I think I prefer the original semantics
because the option always shows the right information and does what it says (and
nothing more). If the concern is around the implementation, I'm happy to
represent it as a map to simplify it. WDYT?

[Wez, 2015/06/02 17:32:56]

I'm fine with landing this simple version of the patch, or moving to the map
implementation in this CL - both seem reasonable!

+  } else {
+    // Remove the right-ctrl mapping and either a leading or trailing comma (but
+    // not both) if there is one.
+    currentMapping = currentMapping.replace(/0x0700e4>0x0700e7,/, '');

[kelvinp, 2015/06/01 18:57:14]

Not in this CL, but i think it would be more natural to use a dictionary (or
simply an object) to represent the key mappings.  This would avoid all those
regular expressions below.

[Wez, 2015/06/01 19:47:57]

+1

+    currentMapping = currentMapping.replace(/,{0,1}0x0700e4>0x0700e7/, '');
+  }
+  this.setRemapKeys(currentMapping);
+};
+
+/**
  * Sends a Ctrl-Alt-Del sequence to the remoting client.
  *
  * @return {void} Nothing.