Fix issue with switching to the same frame twice in a row

lib/capybara/webkit/browser.rb

@@ -83,7 +83,7 @@ module Capybara::Webkit
 
     def frame_focus(selector=nil)
       if selector.respond_to?(:base)
-        selector.base.invoke('focus')
+        selector.base.invoke("focus_frame")
       elsif selector.is_a? Fixnum
         command("FrameFocus", "", selector.to_s)
       elsif selector

spec/integration/session_spec.rb

@@ -325,6 +325,16 @@ describe Capybara::Session do
         end
       end
     end
+
+    it "can swap to the same frame multiple times" do
+      subject.visit("/")
+      subject.within_frame("a_frame") do
+        expect(subject).to have_content("Page A")
+      end
+      subject.within_frame("a_frame") do
+        expect(subject).to have_content("Page A")
+      end
+    end
   end
 
   context 'click tests' do

src/Node.cpp

@@ -11,7 +11,7 @@ void Node::start() {
   QString functionName = functionArguments.takeFirst();
   QString allowUnattached = functionArguments.takeFirst();
   InvocationResult result = page()->invokeCapybaraFunction(functionName, allowUnattached == "true", functionArguments);
-  if (functionName == "focus") {
+  if (functionName == "focus_frame") {
     page()->setCurrentFrameParent(page()->currentFrame()->parentFrame());
   }
   finish(&result);

src/capybara.js

@@ -357,6 +357,14 @@ Capybara = {
     this.getNode(index).focus();
   },
 
+  focus_frame: function(index) {
+    var elem = this.getNode(index);
+    if (elem === document.activeElement) {
+      elem.blur();
+    }
+    elem.focus();
+  },
+
   selectOption: function(index) {
     var optionNode = this.getNode(index);
     var selectNode = optionNode.parentNode;