Change ppapi_simple to support pixel format selection.

native_client_sdk/src/examples/demo/flock/flock.cc

Index: native_client_sdk/src/examples/demo/flock/flock.cc
===================================================================
--- native_client_sdk/src/examples/demo/flock/flock.cc	(revision 217039)
+++ native_client_sdk/src/examples/demo/flock/flock.cc	(working copy)
@@ -116,7 +116,7 @@
 
   g_goose_sprite = new Sprite(buffer, pp::Size(fmt.width, fmt.height), 0);
 
-  PSContext2D_t* ctx = PSContext2DAllocate();
+  PSContext2D_t* ctx = PSContext2DAllocate(PP_IMAGEDATAFORMAT_BGRA_PREMUL);
   ResetFlock(ctx, 50);
   while (1) {
     PSEvent* event;