Add stats collection for telemetry startup.warm.blank_page test.

components/html_viewer/html_frame_tree_manager.h

Index: components/html_viewer/html_frame_tree_manager.h
diff --git a/components/html_viewer/html_frame_tree_manager.h b/components/html_viewer/html_frame_tree_manager.h
index ea807b8e62b2ed5033f2965c546062f81ac5b56b..1d58f89aebe2b3f5094592e45db772f8e7ca766d 100644
--- a/components/html_viewer/html_frame_tree_manager.h
+++ b/components/html_viewer/html_frame_tree_manager.h
@@ -18,7 +18,6 @@ class WebView;
 }
 
 namespace mojo {
-class ApplicationImpl;
 class View;
 }
 
@@ -40,7 +39,6 @@ class HTMLFrameTreeManager {
   // Close() when done.
   static HTMLFrame* CreateFrameAndAttachToTree(
       GlobalState* global_state,
-      mojo::ApplicationImpl* app,
       mojo::View* view,
       scoped_ptr<DocumentResourceWaiter> resource_waiter,
       HTMLFrameDelegate* delegate);