Add a hang monitor for Pepper plugins

chrome/browser/ui/hung_plugin_tab_helper.h

+// Copyright (c) 2012 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_BROWSER_UI_HUNG_PLUGIN_TAB_HELPER_H_
+#define CHROME_BROWSER_UI_HUNG_PLUGIN_TAB_HELPER_H_
+
+#include <map>
+
+#include "base/file_path.h"
+#include "base/memory/linked_ptr.h"
+#include "base/string16.h"
+#include "base/time.h"
+#include "base/timer.h"
+
+class FilePath;
+
+namespace content {
+class WebContents;
+}
+
+// Manages per-tab state with regard to hung plugins. This only handles
+// Pepper plugins which we know are windowless. Hung NPAPI plugins (which
+// may have native windows) can not be handled with infobars and have a
+// separate OS-specific hang monitoring.
+//
+// Our job is:
+// - Pop up an infobar when a plugin is hung.
+// - Terminate the plugin process if the user so chooses.
+// - Periodically re-show the hung plugin infobar if the user closes it without
+//   terminating the plugin.
+// - Hide the infobar if the plugin starts responding again.
+// - Keep track of all of this for any number of plugins.
+class HungPluginTabHelper {
+ public:
+  HungPluginTabHelper(content::WebContents* contents);

[yzshen1, 2012/04/11 18:30:46]

explicit, please.

+  ~HungPluginTabHelper();
+
+  void PluginCrashed(const FilePath& plugin_path);
+
+  void PluginHungStatusChanged(int plugin_child_id,
+                               const FilePath& plugin_path,
+                               bool is_hung);
+
+ private:
+  class InfoBarDelegate;
+  friend class InfoBarDelegate;
+
+  // Per-plugin state (since there could be more than one plugin hung). The
+  // integer key is the child process ID of the plugin process. This maintains
+  // the state for all plugins on this page that are currently hung, whether or
+  // not we're currently showing the infobar.
+  struct PluginState {
+    // Initializes the plugin state to be a hung plugin.
+    PluginState(const FilePath& p, const string16& n);
+    ~PluginState();
+
+    // True when the plugin is currently hung.
+    bool is_hung;

[yzshen1, 2012/04/11 18:30:46]

This member is not used.

+
+    // Time when the infobar for this plugin was last closed. This will be
+    // is_null() if the bar for this plugin has not been closed since it became
+    // hung.
+    base::TimeTicks bar_closed_time;

[yzshen1, 2012/04/11 18:30:46]

This member is not useful, either.

+
+    FilePath path;
+    string16 name;
+
+    // Possibly-null if we're not showing an infobar right now.
+    InfoBarDelegate* info_bar;
+
+    // Time to delay before re-showing the infobar for a hung plugin. This is
+    // increased each time the user cancels it.
+    base::TimeDelta next_reshow_delay;
+
+    // Handles calling the helper when the infobar should be re-shown.
+    base::Timer timer;
+
+   private:
+    // Since the scope of the timer manages our callback, this struct should
+    // not be copied.
+    DISALLOW_COPY_AND_ASSIGN(PluginState);
+  };
+  typedef std::map<int, linked_ptr<PluginState> > PluginStateMap;
+
+  // Called by an infobar when the user selects to kill the plugin.
+  void KillPlugin(int child_id);
+
+  // Called by an infobar when the user presses the close button to dismiss the
+  // bar without doing anything.
+  void BarClosed(int child_id);
+
+  // Called on a timer for a hung plugin if the bar is closed to re-show the

[yzshen1, 2012/04/11 18:30:46]

nit: please consider removing the "if the bar is closed" part.

+  // bar.
+  void OnReshowTimer(int child_id);
+
+  // Shows the bar for the plugin identified by the given state, updating the
+  // state accordingly. The plugin must not have an infobar already.
+  void ShowBar(int child_id, PluginState* state);
+
+  // Closes the infobar associated with the given state. Note that this can
+  // be called even if the bar is not opened, in which case it will do nothing.
+  void CloseBar(PluginState* state);
+
+  content::WebContents* contents_;
+
+  // All currently hung plugins.
+  PluginStateMap hung_plugins_;
+
+  DISALLOW_COPY_AND_ASSIGN(HungPluginTabHelper);
+};
+
+#endif  // CHROME_BROWSER_UI_HUNG_PLUGIN_TAB_HELPER_H_