Early wait on texture resource sync points in gl_renderer.

cc/output/gl_renderer.cc

Index: cc/output/gl_renderer.cc
diff --git a/cc/output/gl_renderer.cc b/cc/output/gl_renderer.cc
index 7123edf5b850cf2711116023d392c0be92a6fe2f..70fe1f18dedd5516ce552eb6b68e485fa1e98d93 100644
--- a/cc/output/gl_renderer.cc
+++ b/cc/output/gl_renderer.cc
@@ -476,6 +476,18 @@ void GLRenderer::DoNoOp() {
   GLC(gl_, gl_->Flush());
 }
 
+void GLRenderer::DoPrelockQuad(DrawingFrame* frame, const DrawQuad* quad) {
+  switch (quad->material) {
+    case DrawQuad::TILED_CONTENT: {
+      const TileDrawQuad* q = TileDrawQuad::MaterialCast(quad);
+      ResourceProvider::ScopedReadLockGL lock(resource_provider_,

[enne (OOO), 2014/08/13 00:20:54]

I'm not sure that I follow what this is trying to do.  A scoped read lock will
lock and unlock right here.  Is that intentional?

[vmiura, 2014/08/13 01:01:32]

Yes it's intentional, in this case taking the lock is taken temporarily to force
any pending mailbox sync point to be checked.

Here:

ResourceProvider::LockForRead(ResourceId id) {
...
    DCHECK(gl);
    if (resource->mailbox.sync_point()) {
      GLC(gl, gl->WaitSyncPointCHROMIUM(resource->mailbox.sync_point()));
      resource->mailbox.set_sync_point(0);
    }
}

[vmiura, 2014/08/13 22:50:39]

No longer applicable.

+                                              q->resource_id);
+    } break;
+    default:
+      break;
+  }
+}
+
 void GLRenderer::DoDrawQuad(DrawingFrame* frame, const DrawQuad* quad) {
   DCHECK(quad->rect.Contains(quad->visible_rect));
   if (quad->material != DrawQuad::TEXTURE_CONTENT) {