Make info button appear only when mouse is over the panel or the panel has focus.

chrome/browser/ui/panels/panel_browser_frame_view.h

Index: chrome/browser/ui/panels/panel_browser_frame_view.h
===================================================================
--- chrome/browser/ui/panels/panel_browser_frame_view.h	(revision 86006)
+++ chrome/browser/ui/panels/panel_browser_frame_view.h	(working copy)
@@ -7,6 +7,7 @@
 #pragma once
 
 #include "base/gtest_prod_util.h"
+#include "base/message_loop.h"
 #include "base/scoped_ptr.h"
 #include "chrome/browser/ui/views/frame/browser_non_client_frame_view.h"
 #include "chrome/browser/ui/views/tab_icon_view.h"
@@ -66,6 +67,7 @@
  private:
   friend class PanelBrowserViewTest;
   FRIEND_TEST_ALL_PREFIXES(PanelBrowserViewTest, CreatePanel);
+  FRIEND_TEST_ALL_PREFIXES(PanelBrowserViewTest, ShowOrHideInfoButton);
 
   enum PaintState {
     NOT_PAINTED,
@@ -73,6 +75,30 @@
     PAINT_AS_ACTIVE
   };
 
+  class MouseWatcher : public MessageLoopForUI::Observer {
+   public:
+    explicit MouseWatcher(PanelBrowserFrameView* view);
+    virtual ~MouseWatcher();
+
+    virtual bool IsCursorInViewBounds() const;
+
+  #if defined(OS_WIN)
+    virtual void WillProcessMessage(const MSG& msg) OVERRIDE { }
+    virtual void DidProcessMessage(const MSG& msg) OVERRIDE;
+  #else
+    virtual void WillProcessEvent(GdkEvent* event) OVERRIDE { }
+    virtual void DidProcessEvent(GdkEvent* event) OVERRIDE;
+  #endif
+
+   private:
+    void HandleGlobalMouseMoveEvent();
+
+    PanelBrowserFrameView* view_;
+    bool in_view_;

[Dmitry Titov, 2011/05/24 20:21:56]

I saw often in the past the suggestion to keep names of this kind of variables
with the "Is" in them, like: is_mouse_within_

[jianli, 2011/05/24 21:58:56]

Done.

+
+    DISALLOW_COPY_AND_ASSIGN(MouseWatcher);
+  };
+
   // Returns the thickness of the entire nonclient left, right, and bottom
   // borders, including both the window frame and any client edge.
   int NonClientBorderThickness() const;
@@ -88,6 +114,20 @@
   void PaintFrameBorder(gfx::Canvas* canvas);
   void PaintClientEdge(gfx::Canvas* canvas);
 
+  // Called by MouseWatcher to notify if the mouse enters or leaves the window.
+  void OnMouseEnterOrLeaveWindow(bool mouse_entered);
+
+  // Make info button visible if either of the conditions is met:
+  // 1) The panel is active, i.e. having focus.
+  // 2) The mouse is over the panel.
+  void UpdateInfoButtonVisibility(bool active, bool cursor_in_view);
+
+#ifdef UNIT_TEST
+  void set_mouse_watcher(MouseWatcher* mouse_watcher) {
+    mouse_watcher_.reset(mouse_watcher);
+  }
+#endif
+
   // The frame that hosts this view. This is a weak reference such that frame_
   // will always be valid in the lifetime of this view.
   BrowserFrame* frame_;
@@ -103,6 +143,7 @@
   TabIconView* title_icon_;
   views::Label* title_label_;
   gfx::Rect client_view_bounds_;
+  scoped_ptr<MouseWatcher> mouse_watcher_;
 
   DISALLOW_COPY_AND_ASSIGN(PanelBrowserFrameView);
 };