Early wait on texture resource sync points in gl_renderer.

cc/output/direct_renderer.cc

Index: cc/output/direct_renderer.cc
diff --git a/cc/output/direct_renderer.cc b/cc/output/direct_renderer.cc
index ccde85b6e5ef668aa7cf6b4a925527e098ff52ee..e770642bfd9e8be731a869278590a96b36696f13 100644
--- a/cc/output/direct_renderer.cc
+++ b/cc/output/direct_renderer.cc
@@ -226,6 +226,12 @@ void DirectRenderer::DrawFrame(RenderPassList* render_passes_in_draw_order,
   // viewport size is never set.
   output_surface_->Reshape(device_viewport_rect.size(), device_scale_factor);
 
+  // Try to lock resources first.
+  for (size_t i = 0; i < render_passes_in_draw_order->size(); ++i) {
+    RenderPass* pass = render_passes_in_draw_order->at(i);
+    PrelockRenderPass(&frame, pass);
+  }
+
   BeginDrawingFrame(&frame);
   for (size_t i = 0; i < render_passes_in_draw_order->size(); ++i) {
     RenderPass* pass = render_passes_in_draw_order->at(i);
@@ -329,6 +335,18 @@ void DirectRenderer::SetScissorTestRectInDrawSpace(
 
 void DirectRenderer::FinishDrawingQuadList() {}
 
+void DirectRenderer::PrelockRenderPass(DrawingFrame* frame,
+                                       const RenderPass* render_pass) {
+  const QuadList& quad_list = render_pass->quad_list;
+  int i = 0;
+  for (QuadList::ConstBackToFrontIterator it = quad_list.BackToFrontBegin();
+       it != quad_list.BackToFrontEnd();
+       ++it) {

[danakj, 2014/08/13 13:52:12]

You can IterateResources here to get each of the resources on each quad. Then
you don't need a switch on the quad material type.

https://code.google.com/p/chromium/codesearch#chromium/src/cc/quads/draw_quad...

Once you have all the resources, instead of doing a Lock/Unlock, how about we
just add an API to wait on any sync points. Something like:

ResourceProvider::WaitSyncPointIfNeeded(ResourceId id) {
  Resource* resource = GetResource(id);
  DCHECK_EQ(resource->exported_count, 0);
  DCHECK(resource->allocated);
  if (!resource is gl type with gl_id) return;
  if (!syncpoint) return;
  DCHECK(resource->mailbox.IsValid);
  WaitSyncPoint(syncpoint);
}

Then we don't need a virtual method and the GL/Software renderers don't need to
be involved.

Can we then DCHECK that there's no sync point to wait on in LockForRead instead
of waiting there too?

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

Done.

+    DoPrelockQuad(frame, *it);
+    i++;
+  }
+}
+
 void DirectRenderer::DrawRenderPass(DrawingFrame* frame,
                                     const RenderPass* render_pass) {
   TRACE_EVENT0("cc", "DirectRenderer::DrawRenderPass");