WIP: Surface Synchronization System

cc/ipc/render_pass_struct_traits.cc

 // Copyright 2016 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "cc/ipc/render_pass_struct_traits.h"
 
 #include "base/numerics/safe_conversions.h"
 #include "cc/ipc/shared_quad_state_struct_traits.h"
 
 namespace mojo {
@@ skipping 13 matching lines @@
   }
   (*out)->id = data.id();
   // RenderPass ids are never zero.
   if (!(*out)->id)
     return false;
   (*out)->has_transparent_background = data.has_transparent_background();
 
   mojo::ArrayDataView<cc::mojom::DrawQuadDataView> quads;
   data.GetQuadListDataView(&quads);
   cc::SharedQuadState* last_sqs = nullptr;
+  cc::DrawQuad* last_draw_quad = nullptr;
   for (size_t i = 0; i < quads.size(); ++i) {
     cc::mojom::DrawQuadDataView quad_data_view;
     quads.GetDataView(i, &quad_data_view);
     cc::mojom::DrawQuadStateDataView quad_state_data_view;
     quad_data_view.GetDrawQuadStateDataView(&quad_state_data_view);
 
     cc::DrawQuad* quad =
         AllocateAndConstruct(quad_state_data_view.tag(), &(*out)->quad_list);
     if (!quad)
       return false;
     if (!quads.Read(i, quad))
       return false;
 
     // Read the SharedQuadState.
     cc::mojom::SharedQuadStateDataView sqs_data_view;
     quad_data_view.GetSqsDataView(&sqs_data_view);
     // If there is no seralized SharedQuadState then used the last deseriaized
     // one.
     if (!sqs_data_view.is_null()) {
       last_sqs = (*out)->CreateAndAppendSharedQuadState();
       if (!quad_data_view.ReadSqs(last_sqs))
         return false;
     }
     quad->shared_quad_state = last_sqs;
     if (!quad->shared_quad_state)
       return false;
+
+    // If this quad is a fallback SurfaceDrawQuad then update the previous
+    // primary SurfaceDrawQuad to point to this quad.
+    if (quad->material == cc::DrawQuad::SURFACE_CONTENT) {
+      const cc::SurfaceDrawQuad* surface_draw_quad =
+          cc::SurfaceDrawQuad::MaterialCast(quad);
+      if (surface_draw_quad->surface_draw_quad_type ==
+          cc::SurfaceDrawQuadType::FALLBACK) {
+        if (!last_draw_quad ||
+            last_draw_quad->material != cc::DrawQuad::SURFACE_CONTENT) {
+          return false;
+        }
+        cc::SurfaceDrawQuad* last_surface_draw_quad =
+            static_cast<cc::SurfaceDrawQuad*>(last_draw_quad);
+        // Only one fallback quad is currently supported.
+        if (last_surface_draw_quad->surface_draw_quad_type !=
+            cc::SurfaceDrawQuadType::PRIMARY) {
+          return false;
+        }
+        last_surface_draw_quad->fallback_quad = surface_draw_quad;
+      }
+    }
+    last_draw_quad = quad;
   }
   return true;
 }
 
 }  // namespace mojo