Allow DrawingBuffer to present to a bitmap.

public/platform/WebExternalBitmap.h

Index: public/platform/WebExternalBitmap.h
diff --git a/public/platform/WebGraphicsContext3DProvider.h b/public/platform/WebExternalBitmap.h
similarity index 80%
copy from public/platform/WebGraphicsContext3DProvider.h
copy to public/platform/WebExternalBitmap.h
index dba2216773526377c53b27a9d6830bce0c25fc48..a34687cb908997915d6b9ea985254e53dc5d8d3f 100644
--- a/public/platform/WebGraphicsContext3DProvider.h
+++ b/public/platform/WebExternalBitmap.h
@@ -28,24 +28,24 @@
  * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  */
 
-#ifndef WebGraphicsContext3DProvider_h
-#define WebGraphicsContext3DProvider_h
-
-#include "WebCommon.h"
-
-class GrContext;
+#ifndef WebExternalBitmap_h
+#define WebExternalBitmap_h
 
 namespace WebKit {
-class WebGraphicsContext3D;
 
-class WebGraphicsContext3DProvider {
+struct WebSize;

[jamesr, 2013/07/03 21:53:02]

since you're returning WebSize by value, i think you need to #include the header
that defines it since anyone who uses this header will need to see the
definition of WebSize anyway

+
+class WebExternalBitmap {
 public:
-    virtual ~WebGraphicsContext3DProvider() { }
+    virtual WebSize getSize() = 0;

[jamesr, 2013/07/03 21:53:02]

no 'get' prefix needed for this. just size().

+
+    // Sets the size of the bitmap. This may reallocate the bitmap and
+    // invalidate the pointer returned from getPointer if the size changes.
+    virtual void setSize(WebSize) = 0;
 
-    virtual WebGraphicsContext3D* context3d() = 0;
-    virtual GrContext* grContext() = 0;
+    virtual void* getPointer() = 0;

[jamesr, 2013/07/03 21:53:02]

what is the type of this? is it a pointer into the pixel buffer? that should
probably be uint8* or something similar.

we very very rarely use the 'get' prefix in blink code. i think this should be
named after what it points to

 };
 
 } // namespace WebKit
 
-#endif
+#endif // WebExternalBitmap_h