Add new user script injection point: document_idle.

chrome/renderer/user_script_idle_scheduler.h

Index: chrome/renderer/user_script_idle_scheduler.h
diff --git a/chrome/renderer/user_script_idle_scheduler.h b/chrome/renderer/user_script_idle_scheduler.h
new file mode 100644
index 0000000000000000000000000000000000000000..de1b303396b35fc6873b13b84f636db3b1426366
--- /dev/null
+++ b/chrome/renderer/user_script_idle_scheduler.h
@@ -0,0 +1,58 @@
+// Copyright (c) 2009 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#ifndef CHROME_RENDERER_USER_SCRIPT_IDLE_SCHEDULER_H_
+#define CHROME_RENDERER_USER_SCRIPT_IDLE_SCHEDULER_H_
+
+#include "base/task.h"
+
+class RenderView;
+
+namespace WebKit {
+class WebFrame;
+}
+
+// Implements support for injecting scripts at "document idle". Currently,
+// determining idleness is simple: it is whichever of the following happens
+// first:
+//
+// a) When the initial DOM for a page is complete + kUserScriptIdleTimeout,
+// b) or when the page has completely loaded including all subresources.
+//
+// The intent of this mechanism is to prevent user scripts from slowing down
+// fast pages (run after load), while still allowing them to run relatively
+// timelily for pages with lots of slow subresources.
+class UserScriptIdleScheduler {
+ public:
+  UserScriptIdleScheduler(RenderView* view, WebKit::WebFrame* frame);
+
+  bool has_run() { return has_run_; }
+
+  // Called when the DOM has been completely constructed.
+  void DidFinishDocumentLoad();
+
+  // Called when the document has completed loading.
+  void DidFinishLoad();
+
+  // Called when the client has gone away and we should no longer run scripts.
+  void Cancel();
+
+ private:
+  // Run user scripts, except if they've already run for this frame, or the
+  // frame has been destroyed.
+  void MaybeRun();
+
+  // The RenderView we will call back to when it is time to run scripts.
+  RenderView* view_;
+
+  // The Frame we will run scripts in.
+  WebKit::WebFrame* frame_;
+
+  // Whether we have already run scripts.
+  bool has_run_;
+
+  ScopedRunnableMethodFactory<UserScriptIdleScheduler> method_factory_;
+};
+
+#endif  // CHROME_RENDERER_USER_SCRIPT_IDLE_SCHEDULER_H_