Simplify platform_canvas.h by recognizing that PlatformCanvas does not actually extend

content/plugin/webplugin_proxy.cc

Index: content/plugin/webplugin_proxy.cc
===================================================================
--- content/plugin/webplugin_proxy.cc	(revision 167659)
+++ content/plugin/webplugin_proxy.cc	(working copy)
@@ -451,14 +451,11 @@
     const TransportDIB::Handle& dib_handle,
     const gfx::Rect& window_rect,
     SkAutoTUnref<skia::PlatformCanvas>* canvas) {
-  canvas->reset(new skia::PlatformCanvas);
-  if (!canvas->get()->initialize(
-          window_rect.width(),
-          window_rect.height(),
-          true,
-          dib_handle)) {
-    canvas->reset(NULL);
-  }
+  canvas->reset(skia::CreatePlatformCanvas(window_rect.width(),
+                                           window_rect.height(),
+                                           true,
+                                           dib_handle,
+                                           skia::RETURN_NULL_ON_FAILURE));
   // The canvas does not own the section so we need to close it now.
   CloseHandle(dib_handle);
 }