Moves the notification icon out of the status area overflow.

chrome/browser/ui/views/message_center/tray_watcher_win.cc

Index: chrome/browser/ui/views/message_center/tray_watcher_win.cc
diff --git a/chrome/browser/ui/views/message_center/tray_watcher_win.cc b/chrome/browser/ui/views/message_center/tray_watcher_win.cc
new file mode 100644
index 0000000000000000000000000000000000000000..3da349732f8b208225f71230f3ed2c87c975cfb5
--- /dev/null
+++ b/chrome/browser/ui/views/message_center/tray_watcher_win.cc
@@ -0,0 +1,209 @@
+// Copyright 2014 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 "chrome/browser/ui/views/message_center/tray_watcher_win.h"
+
+namespace message_center {
+namespace {
+
+////////////////////////////////////////////////////////////////////////////////
+// Status Tray API
+
+// The folowing describes the interface to the undocumented Windows Exporer APIs
+// for manipulating with the status tray area.  This code should be used with
+// care as it can change with versions (even minor versions) of Windows.
+
+// ItrayNotify GUID
+[uuid("FB852B2C-6BAD-4605-9551-F15F87830935")] interface ITrayNotify
+    : public IUnknown {
+  STDMETHOD(RegisterCallback)(INotificationCB* callback) = 0;
+  STDMETHOD(SetPreference)(const NOTIFYITEM* notify_item) = 0;
+  STDMETHOD(EnableAutoTray)(BOOL enabled) = 0;
+};
+
+[uuid("D133CE13-3537-48BA-93A7-AFCD5D2053B4")] interface ITrayNotifyWin8
+    : public IUnknown {
+  STDMETHOD(RegisterCallback)(INotificationCB * callback, unsigned long*) = 0;
+  STDMETHOD(UnregisterCallback)(unsigned long*) = 0;
+  STDMETHOD(SetPreference)(NOTIFYITEM const*) = 0;
+  STDMETHOD(EnableAutoTray)(BOOL) = 0;
+  STDMETHOD(DoAction)(BOOL) = 0;
+};
+
+const CLSID CLSID_TrayNotify = {
+    0x25DEAD04,
+    0x1EAC,
+    0x4911,
+    {0x9E, 0x3A, 0xAD, 0x0A, 0x4A, 0xB5, 0x60, 0xFD}};
+
+}  // namespace
+
+TrayWatcherWin::TrayWatcherWin(UINT icon_id, HWND window)
+    : icon_id_(icon_id),
+      window_(window),
+      interface_version_(INTERFACE_VERSION_UNKNOWN) {
+  wchar_t module_name[MAX_PATH];
+  ::GetModuleFileName(NULL, module_name, MAX_PATH);
+
+  file_name_ = module_name;
+}
+
+bool TrayWatcherWin::CreateTrayNotify() {
+  DCHECK(CalledOnValidThread());
+  HRESULT hr = tray_notify_.CreateInstance(CLSID_TrayNotify);
+  if (FAILED(hr))
+    return false;
+
+  base::win::ScopedComPtr<ITrayNotifyWin8> tray_notify_win8;
+  hr = tray_notify_win8.QueryFrom(tray_notify_);
+  if (SUCCEEDED(hr)) {
+    interface_version_ = INTERFACE_VERSION_WIN8;
+    return true;
+  }
+
+  base::win::ScopedComPtr<ITrayNotify> tray_notify_legacy;
+  hr = tray_notify_legacy.QueryFrom(tray_notify_);
+  if (SUCCEEDED(hr)) {
+    interface_version_ = INTERFACE_VERSION_LEGACY;
+    return true;
+  }
+
+  return false;
+}
+
+void TrayWatcherWin::EnsureTrayIconVisible() {
+  DCHECK(CalledOnValidThread());
+
+  if (!CreateTrayNotify()) {
+    VLOG(1) << "Unable to create COM object for ITrayNotify.";
+    return;
+  }
+
+  scoped_ptr<NOTIFYITEM> notify_item = RegisterCallback();
+
+  // If the user has already hidden us explicitly, try to honor their choice by
+  // not changing anything.
+  if (notify_item->dwPreference == PREFERENCE_SHOW_NEVER)
+    return;
+
+  // If we are already on the taskbar, return since nothing needs to be done.
+  if (notify_item->dwPreference == PREFERENCE_SHOW_ALWAYS)
+    return;
+
+  notify_item->dwPreference = PREFERENCE_SHOW_ALWAYS;
+
+  SendNotifyItemUpdate(notify_item.Pass());
+}
+
+scoped_ptr<NOTIFYITEM> TrayWatcherWin::RegisterCallback() {
+  // |notify_item_| is used to store the result of the callback from
+  // Explorer.exe

[Dmitry Titov, 2014/03/18 22:34:13]

maybe add "which happens synchronously once callback is registered"? It is not
readily obvious from the code, although I think this is what happens, right?

[dewittj, 2014/03/19 18:36:15]

Done.

+  DCHECK(notify_item_.get() == NULL);
+
+  // TODO(dewittj): Add UMA logging here to report if either of our strategies
+  // has a tendency to fail on particular versions of Windows.
+  switch (interface_version_) {
+    case INTERFACE_VERSION_WIN8:
+      if (!RegisterCallbackWin8())
+        VLOG(1) << "Unable to successfully run RegisterCallbackWin8.";
+      break;
+    case INTERFACE_VERSION_LEGACY:
+      if (!RegisterCallbackLegacy())
+        VLOG(1) << "Unable to successfully run RegisterCallbackLegacy.";
+      break;
+    default:
+      NOTREACHED();
+  }
+
+  return notify_item_.Pass();
+}
+
+void TrayWatcherWin::SendNotifyItemUpdate(scoped_ptr<NOTIFYITEM> notify_item) {
+  if (interface_version_ == INTERFACE_VERSION_LEGACY) {
+    base::win::ScopedComPtr<ITrayNotify> tray_notify;
+    HRESULT hr = tray_notify.QueryFrom(tray_notify_);
+    if (SUCCEEDED(hr))
+      tray_notify->SetPreference(notify_item.get());
+  } else if (interface_version_ == INTERFACE_VERSION_WIN8) {
+    base::win::ScopedComPtr<ITrayNotifyWin8> tray_notify;
+    HRESULT hr = tray_notify.QueryFrom(tray_notify_);
+    if (SUCCEEDED(hr))
+      tray_notify->SetPreference(notify_item.get());
+  }
+}
+
+STDMETHODIMP_(ULONG) TrayWatcherWin::AddRef() {
+  DCHECK(CalledOnValidThread());
+  return base::win::IUnknownImpl::AddRef();
+}
+
+STDMETHODIMP_(ULONG) TrayWatcherWin::Release() {
+  DCHECK(CalledOnValidThread());
+  return base::win::IUnknownImpl::Release();
+}
+
+STDMETHODIMP TrayWatcherWin::QueryInterface(REFIID riid, PVOID* ptr_void) {
+  DCHECK(CalledOnValidThread());
+  if (riid == __uuidof(INotificationCB)) {
+    *ptr_void = static_cast<INotificationCB*>(this);
+    AddRef();
+    return S_OK;
+  }
+
+  return base::win::IUnknownImpl::QueryInterface(riid, ptr_void);
+}
+
+STDMETHODIMP TrayWatcherWin::Notify(ULONG event, NOTIFYITEM* notify_item) {
+  DCHECK(CalledOnValidThread());
+  DCHECK(notify_item);
+  if (notify_item->hWnd != window_ || notify_item->uID != icon_id_ ||
+      base::string16(notify_item->pszExeName) != file_name_) {
+    return S_OK;
+  }
+
+  notify_item_.reset(new NOTIFYITEM(*notify_item));
+  return S_OK;
+}
+
+TrayWatcherWin::~TrayWatcherWin() { DCHECK(CalledOnValidThread()); }
+
+bool TrayWatcherWin::RegisterCallbackWin8() {
+  base::win::ScopedComPtr<ITrayNotifyWin8> tray_notify_win8;
+  HRESULT hr = tray_notify_win8.QueryFrom(tray_notify_);
+  if (FAILED(hr))
+    return false;
+
+  // The following two lines cause Windows Explorer to call us back with all the
+  // existing tray icons and their preference.  It would also presumably notify
+  // us if changes were made in realtime while we registered as a callback, but
+  // we just want to modify our own entry so we immediately unregister.
+  unsigned long callback_id = 0;
+  tray_notify_win8->RegisterCallback(this, &callback_id);
+  tray_notify_win8->UnregisterCallback(&callback_id);
+
+  return true;
+}
+
+bool TrayWatcherWin::RegisterCallbackLegacy() {
+  base::win::ScopedComPtr<ITrayNotify> tray_notify;
+  HRESULT hr = tray_notify.QueryFrom(tray_notify_);
+  if (FAILED(hr))
+    return false;
+
+  // The following two lines cause Windows Explorer to call us back with all the
+  // existing tray icons and their preference.  It would also presumably notify
+  // us if changes were made in realtime while we registered as a callback.  In
+  // this version of the API, there can be only one registered callback so it is
+  // better to unregister as soon as possible.
+  // TODO(dewittj): Try to notice if the notification area icon customization
+  // window is open and postpone this call until the user closes it;
+  // registering the callback while the window is open can cause stale data to
+  // be displayed to the user.
+  tray_notify->RegisterCallback(this);
+  tray_notify->RegisterCallback(NULL);
+
+  return true;
+}
+
+}  // namespace message_center