[win] Clicking on the taskbar icon should hide the launcher.

chrome/browser/ui/views/app_list/app_list_controller_win.cc

 // 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.
 
 #include <sstream>
 
 #include "base/command_line.h"
 #include "base/file_util.h"
 #include "base/lazy_instance.h"
 #include "base/memory/singleton.h"
@@ skipping 681 matching lines @@
   if (!current_view_)
     return;
 
   // First get the taskbar and jump lists windows (the jump list is the
   // context menu which the taskbar uses).
   HWND jump_list_hwnd = FindWindow(L"DV2ControlHost", NULL);
   HWND taskbar_hwnd = FindWindow(kTrayClassName, NULL);
 
   HWND app_list_hwnd = GetAppListHWND();
 
-  // Get the focused window, and check if it is one of these windows. Keep
-  // checking it's parent until either we find one of these windows, or there
-  // is no parent left.
+  // Get the focused window. According to MSDN this will be NULL in some cases,
+  // "such as when a window is losing activation". In these cases we do not hide
+  // the launcher. In other cases, we will keep the launcher open if:
+  // - a jump list window has focus, or
+  // - the right mouse button is down and the taskbar has focus, or
+  // - the launcher has regained focus.
+  // This is enough to allow the launcher to be pinned via the right click menu.
   HWND focused_hwnd = GetForegroundWindow();
+  if (!focused_hwnd)
+    return;
+
   while (focused_hwnd) {
     if (focused_hwnd == jump_list_hwnd ||
-        focused_hwnd == taskbar_hwnd ||
         focused_hwnd == app_list_hwnd) {
       return;
     }
+    if (focused_hwnd == taskbar_hwnd) {
+      int right_button =
+          GetSystemMetrics(SM_SWAPBUTTON) ? VK_LBUTTON : VK_RBUTTON;
+      bool right_button_down = GetAsyncKeyState(right_button) < 0;
+      if (right_button_down)
+        return;
+
+      break;
+    }
     focused_hwnd = GetParent(focused_hwnd);
   }
 
   // If we get here, the focused window is not the taskbar, it's context menu,
   // or the app list, so close the app list.
   DismissAppList();
 }
 
 HWND AppListController::GetAppListHWND() const {
 #if defined(USE_AURA)
@@ skipping 102 matching lines @@
 
 }  // namespace
 
 namespace chrome {
 
 AppListService* GetAppListServiceWin() {
   return AppListController::GetInstance();
 }
 
 }  // namespace chrome