diff --git a/engine/public/web/WebView.h b/engine/public/web/WebView.h
index 19dcc8dbe52..842015fa8e8 100644
--- a/engine/public/web/WebView.h
+++ b/engine/public/web/WebView.h
@@ -37,6 +37,8 @@
 #include "sky/engine/public/web/WebPageVisibilityState.h"
 #include "sky/engine/public/web/WebWidget.h"
 
+class GURL;
+
 namespace blink {
 
 class WebFrame;
@@ -48,6 +50,9 @@ struct WebPoint;
 
 class WebView : public WebWidget {
 public:
+    // I've added this here so that it dies when WebView does. :)
+    static bool shouldUseWebView(const GURL& url);
+
     // Initialization ------------------------------------------------------
 
     // Creates a WebView that is NOT yet initialized. You will need to
diff --git a/engine/web/WebViewImpl.cpp b/engine/web/WebViewImpl.cpp
index 342bd53d669..10ae28b364b 100644
--- a/engine/web/WebViewImpl.cpp
+++ b/engine/web/WebViewImpl.cpp
@@ -83,6 +83,7 @@
 #include "sky/engine/wtf/CurrentTime.h"
 #include "sky/engine/wtf/RefPtr.h"
 #include "sky/engine/wtf/TemporaryChange.h"
+#include "url/gurl.h"
 
 // Get rid of WTF's pow define so we can use std::pow.
 #undef pow
@@ -92,6 +93,20 @@ namespace blink {
 
 // WebView ----------------------------------------------------------------
 
+bool WebView::shouldUseWebView(const GURL& url)
+{
+    std::string filename = url.ExtractFileName();
+    int hashStart = filename.find('#');
+    if (hashStart != -1)
+        filename.resize(hashStart);
+    int queryStart = filename.find('?');
+    if (queryStart != -1)
+        filename.resize(queryStart);
+    // For now .dart indicates we should use SkyView. Eventually we'll
+    // use SkyView for all urls regardless of file extension.
+    return !EndsWith(filename, ".dart", false);
+}
+
 WebView* WebView::create(WebViewClient* client)
 {
     // Pass the WebViewImpl's self-reference to the caller.
diff --git a/shell/ui/engine.cc b/shell/ui/engine.cc
index b16d44e6733..e3df08d99b7 100644
--- a/shell/ui/engine.cc
+++ b/shell/ui/engine.cc
@@ -171,13 +171,14 @@ void Engine::OnInputEvent(InputEventPtr event) {
 }
 
 void Engine::LoadURL(const mojo::String& url) {
-  // Enable SkyView here.
-  if (false) {
+  if (!WebView::shouldUseWebView(responseURL)) {
     sky_view_ = blink::SkyView::Create(this);
     sky_view_->Load(GURL(url));
     return;
   }
 
+  LOG(WARNING) << ".sky support is deprecated, please use .dart for main()";
+
   // Something bad happens if you try to call WebView::close and replace
   // the webview.  So for now we just load into the existing one. :/
   if (!web_view_)
diff --git a/viewer/document_view.cc b/viewer/document_view.cc
index f9fe5de87d6..e8eda02094c 100644
--- a/viewer/document_view.cc
+++ b/viewer/document_view.cc
@@ -158,21 +158,24 @@ void DocumentView::OnEmbed(
 void DocumentView::OnViewManagerDisconnected(mojo::ViewManager* view_manager) {
   // TODO(aa): Need to figure out how shutdown works.
 }
-
 void DocumentView::Load(mojo::URLResponsePtr response) {
-  // Enable SkyView here.
-  if (false) {
+  GURL responseURL(response->url);
+
+  if (!blink::WebView::shouldUseWebView(responseURL)) {
     sky_view_ = blink::SkyView::Create(this);
     initializeLayerTreeView();
-    sky_view_->Load(GURL(response->url), response.Pass());
+    sky_view_->Load(responseURL, response.Pass());
     return;
   }
 
+  if (!RuntimeFlags::Get().testing())
+    LOG(WARNING) << ".sky support is deprecated, please use .dart for main()";
+
   web_view_ = blink::WebView::create(this);
   ConfigureSettings(web_view_->settings());
   web_view_->setMainFrame(blink::WebLocalFrame::create(this));
   web_view_->mainFrame()->loadFromDataPipeWithURL(
-      response->body.Pass(), GURL(response->url));
+      response->body.Pass(), responseURL);
 }
 
 void DocumentView::initializeLayerTreeView() {