SideBySide2: Document Shift-{Left,Right} in ? help popup

Shift-Left and Shift-Right can be used to transfer focus between
the two CM3 instances.

Change-Id: Ifd2976d77d2be25c9af673580fa123c6f086ef1b

gerrit-gwtexpui/src/main/java/com/google/gwtexpui/globalkey/client/KeyCommand.java

@@ -74,6 +74,12 @@ public abstract class KeyCommand implements KeyPressHandler {
       case KeyCodes.KEY_ESCAPE:
         namedKey(b, KeyConstants.I.keyEsc());
         break;
+      case KeyCodes.KEY_LEFT:
+        namedKey(b, KeyConstants.I.keyLeft());
+        break;
+      case KeyCodes.KEY_RIGHT:
+        namedKey(b, KeyConstants.I.keyRight());
+        break;
       default:
         b.openSpan();
         b.setStyleName(KeyResources.I.css().helpKey());

gerrit-gwtexpui/src/main/java/com/google/gwtexpui/globalkey/client/KeyConstants.java

@@ -35,4 +35,6 @@ public interface KeyConstants extends Constants {
   String keyShift();
   String keyEnter();
   String keyEsc();
+  String keyLeft();
+  String keyRight();
 }

gerrit-gwtexpui/src/main/java/com/google/gwtexpui/globalkey/client/KeyConstants.properties

@@ -13,3 +13,5 @@ keyMeta = Meta
 keyShift = Shift
 keyEnter = Enter
 keyEsc = Esc
+keyLeft = Left
+keyRight = Right

gerrit-gwtui/src/main/java/com/google/gerrit/client/diff/SideBySide2.java

@@ -403,6 +403,9 @@ public class SideBySide2 extends Screen {
     super.registerKeys();
 
     keysNavigation.add(new UpToChangeCommand2(revision, 0, 'u'));
+    keysNavigation.add(
+        new NoOpKeyCommand(KeyCommand.M_SHIFT, KeyCodes.KEY_LEFT, PatchUtil.C.focusSideA()),
+        new NoOpKeyCommand(KeyCommand.M_SHIFT, KeyCodes.KEY_RIGHT, PatchUtil.C.focusSideB()));
     keysNavigation.add(
         new NoOpKeyCommand(0, 'j', PatchUtil.C.lineNext()),
         new NoOpKeyCommand(0, 'k', PatchUtil.C.linePrev()));

gerrit-gwtui/src/main/java/com/google/gerrit/client/patches/PatchConstants.java

@@ -49,6 +49,8 @@ public interface PatchConstants extends Constants {
   String chunkNext2();
   String commentPrev();
   String commentNext();
+  String focusSideA();
+  String focusSideB();
   String fileList();
   String expandComment();
   String expandAllCommentsOnCurrentLine();

gerrit-gwtui/src/main/java/com/google/gerrit/client/patches/PatchConstants.properties

@@ -31,6 +31,8 @@ chunkPrev2 = Previous diff chunk
 chunkNext2 = Next diff chunk or search result
 commentPrev = Previous comment
 commentNext = Next comment
+focusSideA = Focus left side
+focusSideB = Focus right side
 fileList = Browse files in patch set
 expandComment = Expand or collapse comment
 expandAllCommentsOnCurrentLine = Expand or collapse all comments on current line