Plugin Power Saver: Replace all "plug-in" with "plugin" for consistency.

Passed chrome-ui-review: https://groups.google.com/a/google.com/d/msg/chrome-ui-review/FwuQ2TWc5n8/H3PSuV4L_cAJ

BUG=467165

TBR=tsepez
(comment changes only in render_messages)

NOPRESUBMIT=true
(legacy LOG messages)

Review URL: https://codereview.chromium.org/1007443004

Cr-Commit-Position: refs/heads/master@{#320782}
diff --git a/content/browser/plugin_data_remover_impl.cc b/content/browser/plugin_data_remover_impl.cc
index f74b3783..019f4b0 100644
--- a/content/browser/plugin_data_remover_impl.cc
+++ b/content/browser/plugin_data_remover_impl.cc
@@ -212,7 +212,7 @@
                                       kClearAllData, max_age);
   }
 
-  // Connects the client side of a newly opened plug-in channel.
+  // Connects the client side of a newly opened plugin channel.
   void ConnectToChannel(const IPC::ChannelHandle& handle, bool is_ppapi) {
     DCHECK(BrowserThread::CurrentlyOn(BrowserThread::IO));
 
@@ -288,7 +288,7 @@
   // The name of the plugin. Use only on the I/O thread.
   std::string plugin_name_;
 
-  // The channel is NULL until we have opened a connection to the plug-in
+  // The channel is NULL until we have opened a connection to the plugin
   // process.
   scoped_ptr<IPC::Channel> channel_;
 };