PrintPreviewHandler: Add a GetPreview test

Bug: None
Change-Id: I3441a7a704df305fcb4379ee46cc00b5d3b3619d
Reviewed-on: https://chromium-review.googlesource.com/740704
Commit-Queue: Rebekah Potter <rbpotter@chromium.org>
Reviewed-by: Lei Zhang <thestig@chromium.org>
Cr-Commit-Position: refs/heads/master@{#512993}

chrome/browser/ui/webui/print_preview/print_preview_handler.h

@@ -123,6 +123,9 @@ class PrintPreviewHandler
   // Protected so unit tests can override.
   virtual PrinterHandler* GetPrinterHandler(printing::PrinterType printer_type);
 
+  // Gets the initiator for the print preview dialog.
+  virtual content::WebContents* GetInitiator() const;
+
   // Register/unregister from notifications of changes done to the GAIA
   // cookie. Protected so unit tests can override.
   virtual void RegisterForGaiaCookieChanges();
@@ -137,6 +140,7 @@ class PrintPreviewHandler
   FRIEND_TEST_ALL_PREFIXES(PrintPreviewHandlerTest, GetPrinters);
   FRIEND_TEST_ALL_PREFIXES(PrintPreviewHandlerTest, GetPrinterCapabilities);
   FRIEND_TEST_ALL_PREFIXES(PrintPreviewHandlerTest, Print);
+  FRIEND_TEST_ALL_PREFIXES(PrintPreviewHandlerTest, GetPreview);
   class AccessTokenService;
 
   content::WebContents* preview_web_contents() const;
@@ -247,9 +251,6 @@ class PrintPreviewHandler
   void SendCloudPrintJob(const std::string& callback_id,
                          const base::RefCountedBytes* data);
 
-  // Gets the initiator for the print preview dialog.
-  content::WebContents* GetInitiator() const;
-
   // Closes the preview dialog.
   void ClosePreviewDialog();