Add printing tests to ensure window.print() works for subframes.

content/browser/frame_host/render_frame_host_impl.h

Index: content/browser/frame_host/render_frame_host_impl.h
diff --git a/content/browser/frame_host/render_frame_host_impl.h b/content/browser/frame_host/render_frame_host_impl.h
index 3ad52fe107bc449a92e0ac00d9c0b4ba82cea201..ca50a3167096704c3885cac495adf51a16fab7e3 100644
--- a/content/browser/frame_host/render_frame_host_impl.h
+++ b/content/browser/frame_host/render_frame_host_impl.h
@@ -9,8 +9,10 @@
 #include <stdint.h>
 
 #include <map>
+#include <memory>
 #include <set>
 #include <string>
+#include <utility>
 #include <vector>
 
 #include "base/callback.h"
@@ -132,7 +134,7 @@ class CONTENT_EXPORT RenderFrameHostImpl
   int GetFrameTreeNodeId() override;
   const std::string& GetFrameName() override;
   bool IsCrossProcessSubframe() override;
-  const GURL& GetLastCommittedURL() override;
+  const GURL& GetLastCommittedURL() const override;
   url::Origin GetLastCommittedOrigin() override;
   gfx::NativeView GetNativeView() override;
   void AddMessageToConsole(ConsoleMessageLevel level,
@@ -1053,8 +1055,8 @@ class CONTENT_EXPORT RenderFrameHostImpl
   // requests should be queued.
   bool waiting_for_init_;
 
-  typedef std::pair<CommonNavigationParams, BeginNavigationParams>
-      PendingNavigation;
+  using PendingNavigation =
+      std::pair<CommonNavigationParams, BeginNavigationParams>;
   std::unique_ptr<PendingNavigation> pendinging_navigate_;
 
   // Callback for responding when