Revert "Revert 113479 - Revert "Revert 113250 - Add CommandBuffer::SetGetBuffer""

gpu/command_buffer/service/gpu_scheduler.cc

Index: gpu/command_buffer/service/gpu_scheduler.cc
diff --git a/gpu/command_buffer/service/gpu_scheduler.cc b/gpu/command_buffer/service/gpu_scheduler.cc
index eb1db7e3552d9dd9709c1c4b2bceb4de6cd70279..9282e730cbd563323e38e7e42a9d1b151b374387 100644
--- a/gpu/command_buffer/service/gpu_scheduler.cc
+++ b/gpu/command_buffer/service/gpu_scheduler.cc
@@ -24,21 +24,6 @@ GpuScheduler::GpuScheduler(CommandBuffer* command_buffer,
       decoder_(decoder),
       parser_(parser),
       unscheduled_count_(0) {
-  // Map the ring buffer and create the parser.
-  if (!parser) {
-    Buffer ring_buffer = command_buffer_->GetRingBuffer();
-    if (ring_buffer.ptr) {
-      parser_.reset(new CommandParser(ring_buffer.ptr,
-                                      ring_buffer.size,
-                                      0,
-                                      ring_buffer.size,
-                                      0,
-                                      decoder_));
-    } else {
-      parser_.reset(new CommandParser(NULL, 0, 0, 0, 0,
-                                      decoder_));
-    }
-  }
 }
 
 GpuScheduler::~GpuScheduler() {
@@ -48,6 +33,13 @@ void GpuScheduler::PutChanged() {
   TRACE_EVENT1("gpu", "GpuScheduler:PutChanged", "this", this);
 
   CommandBuffer::State state = command_buffer_->GetState();
+
+  // If there is no parser, exit.
+  if (!parser_.get()) {
+    DCHECK_EQ(state.get_offset, state.put_offset);
+    return;
+  }
+
   parser_->set_put(state.put_offset);
   if (state.error != error::kNoError)
     return;
@@ -122,6 +114,26 @@ void GpuScheduler::set_token(int32 token) {
   command_buffer_->SetToken(token);
 }
 
+bool GpuScheduler::SetGetBuffer(int32 transfer_buffer_id) {
+  Buffer ring_buffer = command_buffer_->GetTransferBuffer(transfer_buffer_id);
+  if (!ring_buffer.ptr) {
+    return false;
+  }
+
+  if (!parser_.get()) {
+    parser_.reset(new CommandParser(decoder_));
+  }
+
+  parser_->SetBuffer(
+      ring_buffer.ptr,
+      ring_buffer.size,
+      0,
+      ring_buffer.size);
+
+  SetGetOffset(0);
+  return true;
+}
+
 bool GpuScheduler::SetGetOffset(int32 offset) {
   if (parser_->set_get(offset)) {
     command_buffer_->SetGetOffset(static_cast<int32>(parser_->get()));