Optionally clear PlatformCanvas instances.

skia/ext/bitmap_platform_device_android.cc

Index: skia/ext/bitmap_platform_device_android.cc
===================================================================
--- skia/ext/bitmap_platform_device_android.cc	(revision 126621)
+++ skia/ext/bitmap_platform_device_android.cc	(working copy)
@@ -21,6 +21,15 @@
   return NULL;
 }
 
+BitmapPlatformDevice* BitmapPlatformDevice::CreateAndClear(int width,
+                                                           int height,
+                                                           bool is_opaque) {
+  BitmapPlatformDevice* device = Create(width, height, is_opaque);
+  if (!is_opaque)
+    device->accessBitmap(true).eraseARGB(0, 0, 0, 0);
+  return device;
+}
+
 BitmapPlatformDevice* BitmapPlatformDevice::Create(int width, int height,
                                                    bool is_opaque,
                                                    uint8_t* data) {
@@ -31,10 +40,6 @@
   } else {

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

nit: this could now be "else if (!bitmap...)" and you can drop the braces.

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

Done.

     if (!bitmap.allocPixels())
       return NULL;
-    // Follow the logic in SkCanvas::createDevice(), initialize the bitmap if it
-    // is not opaque.
-    if (!is_opaque)
-      bitmap.eraseARGB(0, 0, 0, 0);
   }
   bitmap.setIsOpaque(is_opaque);
   return new BitmapPlatformDevice(bitmap);