Make Graphics3D::SwapBuffers take a completion callback

webkit/plugins/ppapi/ppb_surface_3d_impl.cc

 // Copyright (c) 2010 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 "webkit/plugins/ppapi/ppb_surface_3d_impl.h"
 
 #include "gpu/command_buffer/common/command_buffer.h"
 #include "ppapi/c/dev/ppb_graphics_3d_dev.h"
 #include "webkit/plugins/ppapi/common.h"
 #include "webkit/plugins/ppapi/ppapi_plugin_instance.h"
@@ skipping 33 matching lines @@
                   int32_t attribute,
                   int32_t* value) {
   // TODO(alokp): Implement me.
   return 0;
 }
 
 int32_t SwapBuffers(PP_Resource surface_id,
                     PP_CompletionCallback callback) {
   scoped_refptr<PPB_Surface3D_Impl> surface(
       Resource::GetAs<PPB_Surface3D_Impl>(surface_id));
-  return surface->SwapBuffers();
+  return surface->SwapBuffers(callback);
 }
 
 const PPB_Surface3D_Dev ppb_surface3d = {
   &Create,
   &IsSurface3D,
   &SetAttrib,
   &GetAttrib,
   &SwapBuffers
 };
 
 }  // namespace
 
 PPB_Surface3D_Impl::PPB_Surface3D_Impl(PluginInstance* instance)
     : Resource(instance->module()),
       instance_(instance),
       bound_to_instance_(false),
+      swap_initiated_(false),
+      swap_callback_(PP_BlockUntilComplete()),
       context_(NULL) {
 }
 
 PPB_Surface3D_Impl::~PPB_Surface3D_Impl() {
 }
 
 const PPB_Surface3D_Dev* PPB_Surface3D_Impl::GetInterface() {
   return &ppb_surface3d;
 }
 
@@ skipping 33 matching lines @@
     // TODO(apatrick): Figure out the semantics of binding and resizing.
     context->SwapBuffers();
 
     context->SetSwapBuffersCallback(
         NewCallback(this, &PPB_Surface3D_Impl::OnSwapBuffers));
   }
   context_ = context;
   return true;
 }
 
-bool PPB_Surface3D_Impl::SwapBuffers() {
-  return context_ && context_->SwapBuffers();
+bool PPB_Surface3D_Impl::SwapBuffers(PP_CompletionCallback callback) {
+  if (!context_)
+    return false;
+
+  if (swap_callback_.func) {
+    // Already a pending SwapBuffers that hasn't returned yet.
+    return false;
+  }
+
+  swap_callback_ = callback;
+  return context_->SwapBuffers();
+}
+
+void PPB_Surface3D_Impl::ViewInitiatedPaint() {
+  if (swap_callback_.func) {
+    swap_initiated_ = true;
+  }
+}
+
+void PPB_Surface3D_Impl::ViewFlushedPaint() {
+  if (swap_initiated_ && swap_callback_.func) {
+    // We must clear swap_callback_ before issuing the callback. It will be
+    // common for the plugin to issue another SwapBuffers in response to the
+    // callback, and we don't want to think that a callback is already pending.
+    PP_CompletionCallback callback = PP_BlockUntilComplete();
+    std::swap(callback, swap_callback_);
+    swap_initiated_ = false;
+    PP_RunCompletionCallback(&callback, PP_OK);
+  }
 }
 
 unsigned int PPB_Surface3D_Impl::GetBackingTextureId() {
   return context_ ? context_->GetBackingTextureId() : 0;
 }
 
 void PPB_Surface3D_Impl::OnSwapBuffers() {
   if (bound_to_instance_)
     instance()->CommitBackingTexture();
 }
 
 }  // namespace ppapi
 }  // namespace webkit