ppapi: Send sync point whenever the pepper texture changes.

content/renderer/pepper/pepper_plugin_instance_impl.cc

Index: content/renderer/pepper/pepper_plugin_instance_impl.cc
diff --git a/content/renderer/pepper/pepper_plugin_instance_impl.cc b/content/renderer/pepper/pepper_plugin_instance_impl.cc
index 2168d5a885cc1a5e03fa39a777eb7f41aba0ae25..a17345d074283a8f9df6134ed9c75caa8fb2dbe0 100644
--- a/content/renderer/pepper/pepper_plugin_instance_impl.cc
+++ b/content/renderer/pepper/pepper_plugin_instance_impl.cc
@@ -727,9 +727,21 @@ void PepperPluginInstanceImpl::ScrollRect(int dx,
   }
 }
 
+static void IgnoreCallback(uint32, bool) {}
+
 void PepperPluginInstanceImpl::CommitBackingTexture() {
-  if (texture_layer_.get())
-    texture_layer_->SetNeedsDisplay();
+  if (!texture_layer_.get())
+    return;
+  PlatformContext3D* context = bound_graphics_3d_->platform_context();
+  gpu::Mailbox mailbox;
+  uint32 sync_point = 0;
+  context->GetBackingMailbox(&mailbox, &sync_point);
+  DCHECK(!mailbox.IsZero());
+  DCHECK_NE(sync_point, 0u);
+  texture_layer_->SetTextureMailbox(
+      cc::TextureMailbox(mailbox, GL_TEXTURE_2D, sync_point),
+      cc::SingleReleaseCallback::Create(base::Bind(&IgnoreCallback)));
+  texture_layer_->SetNeedsDisplay();
 }
 
 void PepperPluginInstanceImpl::InstanceCrashed() {
@@ -1916,16 +1928,16 @@ bool PepperPluginInstanceImpl::PrintPDFOutput(PP_Resource print_output,
 #endif
 }
 
-static void IgnoreCallback(uint32, bool) {}
-
 void PepperPluginInstanceImpl::UpdateLayer() {
   if (!container_)
     return;
 
   gpu::Mailbox mailbox;
+  uint32 sync_point = 0;
   if (bound_graphics_3d_.get()) {
     PlatformContext3D* context = bound_graphics_3d_->platform_context();
-    context->GetBackingMailbox(&mailbox);
+    context->GetBackingMailbox(&mailbox, &sync_point);
+    DCHECK_EQ(!mailbox.IsZero(), sync_point != 0);

[dmichael (off chromium), 2014/03/04 16:49:08]

nit:
So you're asserting that either:
the mailbox and the sync_point are *both* valid
or
the mailbox and the sync_point are both zero?
...is that the intent?

I think it would be clearer to either just do those cases explicitly:
DCHECK((mailbox.IsZero() && sync_point == 0) ||
       (!mailbox.IsZero() && sync_point != 0));
or at least remove the negations so there's less to think about:
DCHECK_EQ(mailbox.IsZero(), sync_point == 0);

[danakj, 2014/03/04 16:55:10]

Yep.
Ok!

   }
   bool want_3d_layer = !mailbox.IsZero();
   bool want_2d_layer = bound_graphics_2d_platform_ &&
@@ -1956,7 +1968,7 @@ void PepperPluginInstanceImpl::UpdateLayer() {
       texture_layer_ = cc::TextureLayer::CreateForMailbox(NULL);
       opaque = bound_graphics_3d_->IsOpaque();
       texture_layer_->SetTextureMailbox(
-          cc::TextureMailbox(mailbox, GL_TEXTURE_2D, 0),
+          cc::TextureMailbox(mailbox, GL_TEXTURE_2D, sync_point),
           cc::SingleReleaseCallback::Create(base::Bind(&IgnoreCallback)));
       plugin_layer = texture_layer_;
     } else {