Use shared D3D9 texture to transport the compositor's backing buffer to the browser...

gpu/command_buffer/service/gpu_scheduler.cc

Index: gpu/command_buffer/service/gpu_scheduler.cc
===================================================================
--- gpu/command_buffer/service/gpu_scheduler.cc	(revision 106500)
+++ gpu/command_buffer/service/gpu_scheduler.cc	(working copy)
@@ -4,6 +4,7 @@
 
 #include "gpu/command_buffer/service/gpu_scheduler.h"
 
+#include "base/bind.h"
 #include "base/callback.h"
 #include "base/command_line.h"
 #include "base/compiler_specific.h"
@@ -18,6 +19,9 @@
 using ::base::SharedMemory;
 
 namespace gpu {
+namespace {
+const uint64 kPollFencePeriod = 4;
+}
 
 GpuScheduler::GpuScheduler(CommandBuffer* command_buffer,
                            gles2::GLES2Decoder* decoder,
@@ -56,8 +60,31 @@
   if (state.error != error::kNoError)
     return;
 
+  // Check that the GPU has passed all fences.
+  while (!unschedule_fences_.empty()) {
+    if (glTestFenceNV(unschedule_fences_.front().fence)) {
+      glDeleteFencesNV(1, &unschedule_fences_.front().fence);
+      unschedule_fences_.front().task.Run();
+      unschedule_fences_.pop();
+    } else {
+      SetScheduled(false);
+      MessageLoop::current()->PostDelayedTask(
+          FROM_HERE,
+          base::Bind(&GpuScheduler::SetScheduled, AsWeakPtr(), true),
+          kPollFencePeriod);
+      return;
+    }
+  }
+
+  // One of the unschedule fence tasks might have unscheduled us.
+  if (!IsScheduled())
+    return;
+
   error::Error error = error::kNoError;
   while (!parser_->IsEmpty()) {
+    DCHECK(IsScheduled());
+    DCHECK(unschedule_fences_.empty());
+
     error = parser_->ProcessCommand();
 
     // TODO(piman): various classes duplicate various pieces of state, leading
@@ -127,4 +154,21 @@
   command_processed_callback_.reset(callback);
 }
 
+void GpuScheduler::DeferToFence(base::Closure task) {
+  UnscheduleFence fence;
+
+  glGenFencesNV(1, &fence.fence);
+  glSetFenceNV(fence.fence, GL_ALL_COMPLETED_NV);
+
+  fence.task = task;
+
+  unschedule_fences_.push(fence);
+}
+
+GpuScheduler::UnscheduleFence::UnscheduleFence() : fence(0) {
+}
+
+GpuScheduler::UnscheduleFence::~UnscheduleFence() {
+}
+
 }  // namespace gpu