Teach tools/skydb how to take a URL as a parameter.

sky/tools/debugger/debugger.cc

Index: sky/tools/debugger/debugger.cc
diff --git a/sky/tools/debugger/debugger.cc b/sky/tools/debugger/debugger.cc
index 8b0e0d14cf723b74ed1203114184d0b3d6b4c19a..e4aa111a0abea8f19f4282d6666e3f83be1c564d 100644
--- a/sky/tools/debugger/debugger.cc
+++ b/sky/tools/debugger/debugger.cc
@@ -74,11 +74,13 @@ class SkyDebugger : public mojo::ApplicationDelegate,
 
   virtual void OnViewManagerDisconnected(
       mojo::ViewManager* view_manager) override {
+    CHECK(false); // FIXME: This is dead code, why?
     view_manager_ = nullptr;
     root_ = nullptr;
   }
 
   virtual void OnViewDestroyed(mojo::View* view) override {
+    CHECK(false); // FIXME: This is dead code, why?
     view->RemoveObserver(this);
   }