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

content/browser/frame_host/render_frame_host_impl.cc

 // Copyright 2013 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "content/browser/frame_host/render_frame_host_impl.h"
 
 #include <utility>
 
 #include "base/bind.h"
 #include "base/command_line.h"
@@ skipping 417 matching lines @@
 const std::string& RenderFrameHostImpl::GetFrameName() {
   return frame_tree_node_->frame_name();
 }
 
 bool RenderFrameHostImpl::IsCrossProcessSubframe() {
   if (!parent_)
     return false;
   return GetSiteInstance() != parent_->GetSiteInstance();
 }
 
-const GURL& RenderFrameHostImpl::GetLastCommittedURL() {
+const GURL& RenderFrameHostImpl::GetLastCommittedURL() const {
   return last_committed_url();
 }
 
 url::Origin RenderFrameHostImpl::GetLastCommittedOrigin() {
   // Origin is stored per-FTN, so it's incorrect to call for a non-current RFH.
   CHECK(this == frame_tree_node_->current_frame_host());
   return frame_tree_node_->current_origin();
 }
 
 gfx::NativeView RenderFrameHostImpl::GetNativeView() {
@@ skipping 2823 matching lines @@
   // There is no pending NavigationEntry in these cases, so pass 0 as the
   // pending_nav_entry_id. If the previous handle was a prematurely aborted
   // navigation loaded via LoadDataWithBaseURL, propagate the entry id.
   return NavigationHandleImpl::Create(
       params.url, frame_tree_node_, is_renderer_initiated,
       params.was_within_same_page, params.is_srcdoc, base::TimeTicks::Now(),
       entry_id_for_data_nav, false);  // started_from_context_menu
 }
 
 }  // namespace content