Skip flushes on icon writes for 10x better jumplist perf

ui/gfx/icon_util.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 UI_GFX_ICON_UTIL_H_
 #define UI_GFX_ICON_UTIL_H_
 
 #include <windows.h>
 #include <string>
 #include <vector>
@@ skipping 40 matching lines @@
 //   // Use the icon with a WM_SETICON message
 //   ::SendMessage(hwnd, WM_SETICON, static_cast<WPARAM>(ICON_BIG),
 //                 reinterpret_cast<LPARAM>(icon));
 //
 //   // Destroy the icon when we are done
 //   ::DestroyIcon(icon);
 //
 ///////////////////////////////////////////////////////////////////////////////
 class GFX_EXPORT IconUtil {
  public:
+  // ATOMIC_WRITE ensures that a partially written icon won't be created even if
+  // Chrome crashes part way through, but ATOMIC_WRITE is more expensive than
+  // NORMAL_WRITE. See CreateIconFileFromImageFamily. ATOMIC_WRITE is the
+  // default for historical reasons.
+  enum WriteType { ATOMIC_WRITE, NORMAL_WRITE };
   // The size of the large icon entries in .ico files on Windows Vista+.
   static const int kLargeIconSize = 256;
   // The size of icons in the medium icons view on Windows Vista+. This is the
   // maximum size Windows will display an icon that does not have a 256x256
   // image, even at the large or extra large icons views.
   static const int kMediumIconSize = 48;
 
   // The dimensions for icon images in Windows icon files. All sizes are square;
   // that is, the value 48 means a 48x48 pixel image. Sizes are listed in
   // ascending order.
@@ skipping 48 matching lines @@
   //
   // If |image_family| contains an image larger than 48x48, the resulting icon
   // will contain all sizes up to 256x256. The 256x256 image will be stored in
   // PNG format inside the .ico file. If not, the resulting icon will contain
   // all sizes up to 48x48.
   //
   // The function returns true on success and false otherwise. Returns false if
   // |image_family| is empty.
   static bool CreateIconFileFromImageFamily(
       const gfx::ImageFamily& image_family,
-      const base::FilePath& icon_path);
+      const base::FilePath& icon_path,
+      WriteType write_type = ATOMIC_WRITE);
 
   // Creates a cursor of the specified size from the DIB passed in.
   // Returns the cursor on success or NULL on failure.
   static HICON CreateCursorFromDIB(const gfx::Size& icon_size,
                                    const gfx::Point& hotspot,
                                    const void* dib_bits,
                                    size_t dib_size);
 
  private:
   // The icon format is published in the MSDN but there is no definition of
   // the icon file structures in any of the Windows header files so we need to
   // define these structure within the class. We must make sure we use 2 byte
-  // packing so that the structures are layed out properly within the file.
+  // packing so that the structures are laid out properly within the file.
   // See: http://msdn.microsoft.com/en-us/library/ms997538.aspx
 #pragma pack(push)
 #pragma pack(2)
 
   // ICONDIRENTRY contains meta data for an individual icon image within a
   // .ico file.
   struct ICONDIRENTRY {
     BYTE bWidth;
     BYTE bHeight;
     BYTE bColorCount;
@@ skipping 110 matching lines @@
   // A helper function of CreateSkBitmapFromHICON.
   static SkBitmap CreateSkBitmapFromHICONHelper(HICON icon,
                                                 const gfx::Size& s);
 
   // Prevent clients from instantiating objects of that class by declaring the
   // ctor/dtor as private.
   DISALLOW_IMPLICIT_CONSTRUCTORS(IconUtil);
 };
 
 #endif  // UI_GFX_ICON_UTIL_H_