Optionally clear PlatformCanvas instances.

skia/ext/bitmap_platform_device_linux.h

Index: skia/ext/bitmap_platform_device_linux.h
===================================================================
--- skia/ext/bitmap_platform_device_linux.h	(revision 126621)
+++ skia/ext/bitmap_platform_device_linux.h	(working copy)
@@ -71,9 +71,19 @@
   BitmapPlatformDevice(const SkBitmap& other, BitmapPlatformDeviceData* data);
   virtual ~BitmapPlatformDevice();
 
+  // Constructs a device with size |width| * |height|.with contents initialized

[Alexei Svitkine (slow), 2012/03/16 05:57:56]

Replace the . after |height| with a space.

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

Done.

+  // to zero. |is_opaque| should be set if the caller knows the bitmap will be
+  // completely opaque and allows some optimizations.
   static BitmapPlatformDevice* Create(int width, int height, bool is_opaque);
 
-  // This doesn't take ownership of |data|
+  // Performs the same construction as Create.
+  // Other ports require a separate construction routine because Create does not
+  // initialize the bitmap to 0.
+  static BitmapPlatformDevice* CreateAndClear(int width, int height,
+                                              bool is_opaque);
+
+  // This doesn't take ownership of |data|. If |data| is NULL, the contents

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

is this contingent on |data|'s value? sounds like it's always cleared.

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

My understanding of this code is that if |data| is non-null, then the bitmap
will have the pixel-data contents of |data|.  Otherwise, a 0-initialized bitmap
is created.

+  // of the device are initialized to 0.
   static BitmapPlatformDevice* Create(int width, int height, bool is_opaque,
                                       uint8_t* data);