Create a dummy resource for PluginPlaceholderElement.js.

This prepares for the landing of
  https://codereview.chromium.org/522783002/

which now requires a three-sided change due to changes in how Blink accesses
private script resources.

Part 2: https://codereview.chromium.org/556793006/

BUG=364716

Review URL: https://codereview.chromium.org/570863002

git-svn-id: svn://svn.chromium.org/blink/trunk@181980 bbb929c8-8fbe-4397-9dbb-9b2b20218538

third_party/WebKit/Source/core/html/shadow/PluginPlaceholderElement.js

+/**
+ * This is a placeholder to create the
+ * IDR_PRIVATE_SCRIPT_PLUGINPLACEHOLDERELEMENT_JS resource.
+ *
+ * It will be replaced by a complete file in:
+ *   https://codereview.chromium.org/522783002/
+ */

third_party/WebKit/public/blink_resources.grd

@@ -41,6 +41,7 @@
       <include name="IDR_INSPECTOR_DEBUGGER_SCRIPT_SOURCE_JS" file="../Source/bindings/core/v8/DebuggerScript.js" type="BINDATA"/>
       <include name="IDR_PRIVATE_SCRIPT_DOCUMENTXMLTREEVIEWER_JS" file="../Source/core/xml/DocumentXMLTreeViewer.js" type="BINDATA"/>
       <include name="IDR_PRIVATE_SCRIPT_HTMLMARQUEEELEMENT_JS" file="../Source/core/html/HTMLMarqueeElement.js" type="BINDATA"/>
+      <include name="IDR_PRIVATE_SCRIPT_PLUGINPLACEHOLDERELEMENT_JS" file="../Source/core/html/shadow/PluginPlaceholderElement.js" type="BINDATA"/>
       <include name="IDR_PRIVATE_SCRIPT_PRIVATESCRIPTRUNNER_JS" file="../Source/bindings/core/v8/PrivateScriptRunner.js" type="BINDATA"/>
       <include name="IDR_PICKER_COMMON_JS" file="../Source/web/resources/pickerCommon.js" type="BINDATA"/>
       <include name="IDR_PICKER_COMMON_CSS" file="../Source/web/resources/pickerCommon.css" type="BINDATA"/>