Make Print Preview work correctly at early startup.

Print Preview needs the PDF plugin to work, but plugin loading happens
asynchronously at startup. So querying the PluginService with
GetPluginInfoByPath() may fail because the plugins have not been loaded
yet.

However, since the PDF plugin is a built-in PPAPI plugin, it does not
need to be loaded from disk asynchronously. Since it is already
registered, call GetRegisteredPpapiPluginInfo() instead.

BUG=857074

Change-Id: I729b40329f1de92da6789efbbbae7e2c09ab8b51
Reviewed-on: https://chromium-review.googlesource.com/1175553
Commit-Queue: Lei Zhang <thestig@chromium.org>
Reviewed-by: Tommy Li <tommycli@chromium.org>
Cr-Commit-Position: refs/heads/master@{#583392}

chrome/browser/printing/print_view_manager.cc

@@ -40,15 +40,14 @@ void EnableInternalPDFPluginForContents(int render_process_id,
   // Always enable the internal PDF plugin for the print preview page.
   static const base::FilePath pdf_plugin_path(
       ChromeContentClient::kPDFPluginPath);
-
-  content::WebPluginInfo pdf_plugin;
-  if (!content::PluginService::GetInstance()->GetPluginInfoByPath(
-      pdf_plugin_path, &pdf_plugin)) {
+  auto* plugin_service = content::PluginService::GetInstance();
+  const content::PepperPluginInfo* info =
+      plugin_service->GetRegisteredPpapiPluginInfo(pdf_plugin_path);
+  if (!info)
     return;
-  }
 
   ChromePluginServiceFilter::GetInstance()->OverridePluginForFrame(
-      render_process_id, render_frame_id, GURL(), pdf_plugin);
+      render_process_id, render_frame_id, GURL(), info->ToWebPluginInfo());
 }
 
 }  // namespace