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

chrome/browser/printing/print_view_manager.h

Index: chrome/browser/printing/print_view_manager.h
diff --git a/chrome/browser/printing/print_view_manager.h b/chrome/browser/printing/print_view_manager.h
index 7c6ddf2b397a8ecf48cd257b816b9926ccb51790..69a532bc2e9c1ad77c47c5bf7078c96da158b945 100644
--- a/chrome/browser/printing/print_view_manager.h
+++ b/chrome/browser/printing/print_view_manager.h
@@ -9,6 +9,7 @@
 #include "chrome/browser/printing/print_view_manager_base.h"
 #include "content/public/browser/web_contents_user_data.h"
 #include "printing/features/features.h"
+#include "url/gurl.h"
 
 namespace content {
 class RenderFrameHost;
@@ -21,6 +22,17 @@ namespace printing {
 class PrintViewManager : public PrintViewManagerBase,
                          public content::WebContentsUserData<PrintViewManager> {
  public:
+  class TestDelegate {
+   public:
+    virtual ~TestDelegate() {}
+
+    // Called when the given RFH performs a JS window.print() call. Returns true
+    // to continue processing window.print() normally, or false to immediately
+    // issue an IPC reply.
+    virtual bool ScriptedPrint(
+        const content::RenderFrameHost* render_frame_host);
+  };
+
   ~PrintViewManager() override;
 
 #if BUILDFLAG(ENABLE_BASIC_PRINTING)
@@ -57,6 +69,9 @@ class PrintViewManager : public PrintViewManagerBase,
 
   content::RenderFrameHost* print_preview_rfh() { return print_preview_rfh_; }
 
+  // Used in tests to observe and/or override behavior.
+  void SetTestDelegate(TestDelegate* delegate);
+
  private:
   explicit PrintViewManager(content::WebContents* web_contents);
   friend class content::WebContentsUserData<PrintViewManager>;
@@ -78,14 +93,16 @@ class PrintViewManager : public PrintViewManagerBase,
   base::Closure on_print_dialog_shown_callback_;
 
   // Current state of print preview for this view.
-  PrintPreviewState print_preview_state_;
+  PrintPreviewState print_preview_state_ = NOT_PREVIEWING;
 
   // The current RFH that is print previewing. It should be a nullptr when
   // |print_preview_state_| is NOT_PREVIEWING.
-  content::RenderFrameHost* print_preview_rfh_;
+  content::RenderFrameHost* print_preview_rfh_ = nullptr;
 
   // Keeps track of the pending callback during scripted print preview.
-  content::RenderProcessHost* scripted_print_preview_rph_;
+  content::RenderProcessHost* scripted_print_preview_rph_ = nullptr;
+
+  TestDelegate* test_delegate_ = nullptr;
 
   DISALLOW_COPY_AND_ASSIGN(PrintViewManager);
 };