Revert "Change call-sites now that SkCanvas is not ref-counted"

content/renderer/pepper/pepper_plugin_instance_impl.h

 // Copyright (c) 2012 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.
 
 #ifndef CONTENT_RENDERER_PEPPER_PEPPER_PLUGIN_INSTANCE_IMPL_H_
 #define CONTENT_RENDERER_PEPPER_PEPPER_PLUGIN_INSTANCE_IMPL_H_
 
 #include <stddef.h>
 #include <stdint.h>
 
@@ skipping 821 matching lines @@
   scoped_refptr<PPB_ImageData_Impl> last_printed_page_;
 #endif  // defined(OS_MACOSX)
   // Always when printing to PDF on Linux and when printing for preview on Mac
   // and Win, the entire document goes into one metafile.  However, when users
   // print only a subset of all the pages, it is impossible to know if a call
   // to PrintPage() is the last call. Thus in PrintPage(), just store the page
   // number in |ranges_|. The hack is in PrintEnd(), where a valid |canvas_|
   // is preserved in PrintWebViewHelper::PrintPages. This makes it possible
   // to generate the entire PDF given the variables below:
   //
-  // The most recently used WebCanvas to be used in printEnd(). Caller must
-  // ensure that it remains valid until that point.
-  blink::WebCanvas* canvas_;
+  // The most recently used WebCanvas, guaranteed to be valid.
+  sk_sp<blink::WebCanvas> canvas_;
   // An array of page ranges.
   std::vector<PP_PrintPageNumberRange_Dev> ranges_;
 
   scoped_refptr<ppapi::Resource> gamepad_impl_;
   scoped_refptr<ppapi::Resource> uma_private_impl_;
 
   // The plugin print interface.
   const PPP_Printing_Dev* plugin_print_interface_;
 
   // The plugin 3D interface.
@@ skipping 130 matching lines @@
   // view change events.
   base::WeakPtrFactory<PepperPluginInstanceImpl> view_change_weak_ptr_factory_;
   base::WeakPtrFactory<PepperPluginInstanceImpl> weak_factory_;
 
   DISALLOW_COPY_AND_ASSIGN(PepperPluginInstanceImpl);
 };
 
 }  // namespace content
 
 #endif  // CONTENT_RENDERER_PEPPER_PEPPER_PLUGIN_INSTANCE_IMPL_H_