Moves calling TaskbarList::SetOverlayIcon to a separate thread. It

chrome/browser/ui/views/frame/taskbar_decorator_win.cc

Index: chrome/browser/ui/views/frame/taskbar_decorator_win.cc
diff --git a/chrome/browser/ui/views/frame/taskbar_decorator_win.cc b/chrome/browser/ui/views/frame/taskbar_decorator_win.cc
new file mode 100644
index 0000000000000000000000000000000000000000..72e7424f952303e7ecff4aac39f6b1104931d7c5
--- /dev/null
+++ b/chrome/browser/ui/views/frame/taskbar_decorator_win.cc
@@ -0,0 +1,97 @@
+// Copyright (c) 2013 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/frame/taskbar_decorator.h"
+
+#include <shobjidl.h>
+
+#include "base/bind.h"
+#include "base/location.h"
+#include "base/threading/worker_pool.h"
+#include "base/win/scoped_com_initializer.h"
+#include "base/win/scoped_comptr.h"
+#include "base/win/scoped_gdi_object.h"
+#include "base/win/windows_version.h"
+#include "chrome/browser/profiles/profile_info_util.h"
+#include "chrome/browser/ui/host_desktop.h"
+#include "chrome/browser/ui/views/hwnd_util.h"
+#include "skia/ext/image_operations.h"
+#include "third_party/skia/include/core/SkRect.h"
+#include "ui/gfx/icon_util.h"
+#include "ui/gfx/image/image.h"
+
+namespace chrome {
+
+namespace {
+
+// Responsible for invoking TaskbarList::SetOverlayIcon(). The call to
+// TaskbarList::SetOverlayIcon() runs a nested message loop that proves
+// problematic when called on the UI thread. Additionally it seems the call may
+// take a while to complete. For this reason we call it on a worker thread.
+//
+// Docs for TaskbarList::SetOverlayIcon() say it does nothing if the HWND is not
+// valid.
+void SetOverlayIcon(HWND hwnd, scoped_ptr<SkBitmap> bitmap) {
+  base::win::ScopedCOMInitializer com_initializer;
+  base::win::ScopedComPtr<ITaskbarList3> taskbar;
+  HRESULT result = taskbar.CreateInstance(CLSID_TaskbarList, NULL,
+                                          CLSCTX_INPROC_SERVER);
+  if (FAILED(result) || FAILED(taskbar->HrInit()))
+    return;
+
+  base::win::ScopedGDIObject<HICON> icon;
+  if (bitmap.get()) {
+    const SkBitmap* source_bitmap = NULL;
+    SkBitmap squarer_bitmap;
+    if ((bitmap->width() == profiles::kAvatarIconWidth) &&
+        (bitmap->height() == profiles::kAvatarIconHeight)) {
+      // Shave a couple of columns so the bitmap is more square. So when
+      // resized to a square aspect ratio it looks pretty.
+      int x = 2;
+      bitmap->extractSubset(&squarer_bitmap, SkIRect::MakeXYWH(x, 0,
+          profiles::kAvatarIconWidth - x * 2, profiles::kAvatarIconHeight));
+      source_bitmap = &squarer_bitmap;
+    } else {
+      // The image's size has changed. Resize what we have.
+      source_bitmap = bitmap.get();
+    }
+    // Since the target size is so small, we use our best resizer. Never pass
+    // windows a different size because it will badly hammer it to 16x16.
+    SkBitmap sk_icon = skia::ImageOperations::Resize(
+        *source_bitmap,
+        skia::ImageOperations::RESIZE_LANCZOS3,
+        16, 16);
+    icon.Set(IconUtil::CreateHICONFromSkBitmap(sk_icon));
+    if (!icon.Get())
+      return;
+  }
+  taskbar->SetOverlayIcon(hwnd, icon, L"");
+}
+
+}  // namespace
+
+void DrawTaskbarDecoration(gfx::NativeWindow window, const gfx::Image* image) {
+  // HOST_DESKTOP_TYPE_ASH doesn't use the taskbar.
+  if (base::win::GetVersion() < base::win::VERSION_WIN7 ||
+      chrome::GetHostDesktopTypeForNativeWindow(window) !=
+      chrome::HOST_DESKTOP_TYPE_NATIVE)
+    return;
+
+  HWND hwnd = chrome::HWNDForNativeWindow(window);
+
+  // SetOverlayIcon() does nothing if the window is not visible so testing here
+  // avoids all the wasted effort of the image resizing.
+  if (!::IsWindowVisible(hwnd))
+    return;
+
+  // Copy the image since we're going to use it on a separate thread and
+  // gfx::Image isn't thread safe.
+  scoped_ptr<SkBitmap> bitmap(
+      image ? new SkBitmap(*image->ToSkBitmap()) : NULL);
+  // TaskbarList::SetOverlayIcon() may take a while, so we use slow here.
+  base::WorkerPool::PostTask(
+      FROM_HERE, base::Bind(&SetOverlayIcon, hwnd, Passed(&bitmap)), true);
+}
+
+}  // namespace chrome