Simplify ppapi Graphics3D size propagation a bit

ppapi/thunk/ppb_graphics_3d_api.h

Index: ppapi/thunk/ppb_graphics_3d_api.h
diff --git a/ppapi/thunk/ppb_graphics_3d_api.h b/ppapi/thunk/ppb_graphics_3d_api.h
index 9c2e31228df20bd8c1aa605605948fb7fea05f31..8d590ec9e64bad8118db989a6720fb6ba7e7bb9b 100644
--- a/ppapi/thunk/ppb_graphics_3d_api.h
+++ b/ppapi/thunk/ppb_graphics_3d_api.h
@@ -13,6 +13,10 @@
 #include "ppapi/c/ppb_graphics_3d.h"
 #include "ppapi/thunk/ppapi_thunk_export.h"
 
+namespace gfx {
+class Size;
+}
+
 namespace gpu {
 struct SyncToken;
 }
@@ -36,8 +40,7 @@ class PPAPI_THUNK_EXPORT PPB_Graphics3D_API {
   virtual int32_t SwapBuffersWithSyncToken(
       scoped_refptr<TrackedCallback> callback,
       const gpu::SyncToken& sync_token,
-      int32_t width,
-      int32_t height) = 0;
+      const gfx::Size& size) = 0;
   virtual int32_t GetAttribMaxValue(int32_t attribute, int32_t* value) = 0;
 
   // Graphics3DTrusted API.