Blink: Replace all "plug-in" with "plugin".

Source/core/dom/DOMImplementation.cpp

Index: Source/core/dom/DOMImplementation.cpp
diff --git a/Source/core/dom/DOMImplementation.cpp b/Source/core/dom/DOMImplementation.cpp
index fe2570be534aa6c104d27f4f0ce5f96c3b8015a7..e47b6bce7d252ddbadb6f552d5b8ff1f3ec62c22 100644
--- a/Source/core/dom/DOMImplementation.cpp
+++ b/Source/core/dom/DOMImplementation.cpp
@@ -355,8 +355,8 @@ PassRefPtrWillBeRawPtr<Document> DOMImplementation::createDocument(const String&
         return MediaDocument::create(init);
 
     // Everything else except text/plain can be overridden by plugins. In particular, Adobe SVG Viewer should be used for SVG, if installed.
-    // Disallowing plug-ins to use text/plain prevents plug-ins from hijacking a fundamental type that the browser is expected to handle,
-    // and also serves as an optimization to prevent loading the plug-in database in the common case.
+    // Disallowing plugins to use text/plain prevents plugins from hijacking a fundamental type that the browser is expected to handle,
+    // and also serves as an optimization to prevent loading the plugin database in the common case.
     if (type != "text/plain" && pluginData && pluginData->supportsMimeType(type))
         return PluginDocument::create(init);
     if (isTextMIMEType(type))