create cairo before we hand-off the surface, in case the surface is destroyed

skia/ext/bitmap_platform_device_cairo.h

Index: skia/ext/bitmap_platform_device_cairo.h
diff --git a/skia/ext/bitmap_platform_device_cairo.h b/skia/ext/bitmap_platform_device_cairo.h
index 5b3c46ce8a3fc98e30364bde940308074b3f62d8..8d8f3885a65bd4d687373e326c253b0d276f3c2c 100644
--- a/skia/ext/bitmap_platform_device_cairo.h
+++ b/skia/ext/bitmap_platform_device_cairo.h
@@ -63,8 +63,8 @@ class BitmapPlatformDevice : public SkBitmapDevice, public PlatformDevice {
   // we ever have to share state between some native drawing UI and Skia, like
   // the Windows and Mac versions of this class do.
   //
-  // This object takes ownership of @data.
-  BitmapPlatformDevice(const SkBitmap& other, cairo_surface_t* surface);
+  // This object takes ownership of @cairo.
+  BitmapPlatformDevice(const SkBitmap& other, cairo_t* cairo);
   virtual ~BitmapPlatformDevice();
 
   // Constructs a device with size |width| * |height| with contents initialized