Fix print preview draft page memory leaks.

chrome/renderer/print_web_view_helper_linux.cc

 // Copyright (c) 2011 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 "chrome/renderer/print_web_view_helper.h"
 
 #include "base/file_descriptor_posix.h"
 #include "base/logging.h"
 #include "base/memory/scoped_ptr.h"
 #include "base/metrics/histogram.h"
@@ skipping 20 matching lines @@
   page_params.page_number = page_number;
 
   base::TimeTicks begin_time = base::TimeTicks::Now();
   PrintPageInternal(page_params,
                     print_preview_context_.GetPrintCanvasSize(),
                     print_preview_context_.frame(),
                     print_preview_context_.metafile());
 
   print_preview_context_.RenderedPreviewPage(
       base::TimeTicks::Now() - begin_time);
-  printing::Metafile* page_metafile = NULL;
+  scoped_ptr<printing::Metafile> page_metafile;
   if (print_preview_context_.IsModifiable()) {
-    page_metafile = reinterpret_cast<printing::PreviewMetafile*>(
-        print_preview_context_.metafile())->GetMetafileForCurrentPage();
+    page_metafile.reset(reinterpret_cast<printing::PreviewMetafile*>(
+        print_preview_context_.metafile())->GetMetafileForCurrentPage());
   }
-  PreviewPageRendered(page_number, page_metafile);
+  PreviewPageRendered(page_number, page_metafile.get());
 }
 
 bool PrintWebViewHelper::PrintPages(const PrintMsg_PrintPages_Params& params,
                                     WebFrame* frame,
                                     WebNode* node,
                                     PrepareFrameAndViewForPrint* prepare) {
   printing::NativeMetafile metafile;
   if (!metafile.Init())
     return false;
 
@@ skipping 151 matching lines @@
   canvas->unref();  // SkRefPtr and new both took a reference.
   printing::MetafileSkiaWrapper::SetMetafileOnCanvas(canvas.get(), metafile);
   frame->printPage(params.page_number, canvas.get());
 
   // TODO(myhuang): We should render the header and the footer.
 
   // Done printing. Close the device context to retrieve the compiled metafile.
   if (!metafile->FinishPage())
     NOTREACHED() << "metafile failed";
 }