Optionally clear PlatformCanvas instances.

skia/ext/bitmap_platform_device_win.h

Index: skia/ext/bitmap_platform_device_win.h
===================================================================
--- skia/ext/bitmap_platform_device_win.h	(revision 126621)
+++ skia/ext/bitmap_platform_device_win.h	(working copy)
@@ -35,13 +35,23 @@
   // The shared_section parameter is optional (pass NULL for default behavior).
   // If shared_section is non-null, then it must be a handle to a file-mapping
   // object returned by CreateFileMapping.  See CreateDIBSection for details.
-  static BitmapPlatformDevice* create(HDC screen_dc, int width, int height,
+  // If shared_section is null, the bitmap backing store is not initialized.

[msw, 2012/03/16 07:13:22]

nit: vertical bars around |shared_section|.

[Jeff Timanus, 2012/03/16 15:52:42]

Done.

+  static BitmapPlatformDevice* Create(HDC screen_dc, int width, int height,
                                       bool is_opaque, HANDLE shared_section);
 
   // This version is the same as above but will get the screen DC itself.
-  static BitmapPlatformDevice* create(int width, int height, bool is_opaque,
+  static BitmapPlatformDevice* Create(int width, int height, bool is_opaque,
                                       HANDLE shared_section);
 
+  // Create a BitmapPlatformDevice wit no shared section.  The bitmap is not

[msw, 2012/03/16 07:13:22]

spelling nit: with

[Jeff Timanus, 2012/03/16 15:52:42]

Done.

+  // initialized to 0.
+  static BitmapPlatformDevice* Create(int width, int height, bool is_opaque);
+
+  // Creates a BitmapPlatformDevice instance respecting the parameters as above.
+  // If |is_opaque| is false, then the bitmap is initialzed to 0.
+  static BitmapPlatformDevice* CreateAndClear(int width, int height,
+                                              bool is_opaque);
+
   virtual ~BitmapPlatformDevice();
 
   // PlatformDevice overrides