[code] Fixed the wait for user input after drawing using Python.

A SandboxController is now pushed on the StackViewController and sets the
KDIonContext::sharedContext before drawing, sets a white background and handles
user input after the Python computation to dismiss the drawing screen.

Change-Id: I51b0474365a85e845227379a16d090541fa8ded7

apps/code/sandbox_controller.cpp

@@ -0,0 +1,31 @@
+#include "sandbox_controller.h"
+#include <apps/apps_container.h>
+
+namespace Code {
+
+SandboxController::SandboxController(Responder * parentResponder) :
+  ViewController(parentResponder),
+  m_solidColorView(KDColorWhite)
+{
+}
+
+StackViewController * SandboxController::stackViewController() {
+  return static_cast<StackViewController *>(parentResponder());
+}
+
+void SandboxController::viewWillAppear() {
+  static_cast<AppsContainer *>(const_cast<Container *>(app()->container()))->redrawWindow();
+}
+
+bool SandboxController::handleEvent(Ion::Events::Event event) {
+  if (event == Ion::Events::Home || event == Ion::Events::OnOff) {
+    stackViewController()->pop();
+    return false;
+  }
+  if (event == Ion::Events::OK || event == Ion::Events::Back) {
+    stackViewController()->pop();
+  }
+  return true;
+}
+
+}