Remove a bunch of provisionalDataSource() usage.

components/html_viewer/layout_test_content_handler_impl.cc

Index: components/html_viewer/layout_test_content_handler_impl.cc
diff --git a/components/html_viewer/layout_test_content_handler_impl.cc b/components/html_viewer/layout_test_content_handler_impl.cc
index a76f294b2269246928350a017ed10744e78cba99..ae59e3b4998ffecdc1ea126795fce2bbf426fe49 100644
--- a/components/html_viewer/layout_test_content_handler_impl.cc
+++ b/components/html_viewer/layout_test_content_handler_impl.cc
@@ -24,6 +24,13 @@ class TestHTMLFrame : public HTMLFrame {
     test_interfaces_ = test_interfaces;
   }
 
+  // WebFrameTestProxy expects to be able to get a WebLocalFrame from
+  // Base::GetWebFrame().
+  blink::WebLocalFrame* GetWebFrame() {
+    return web_frame()->isWebLocalFrame() ?
+        web_frame()->toWebLocalFrame() : NULL;
+  }
+
  protected:
   ~TestHTMLFrame() override {}