Avoid GetState IPC call during AllocateRingbuffer.

gpu/command_buffer/client/cmd_buffer_helper.cc

 // Copyright (c) 2012 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 // This file contains the implementation of the command buffer helper class.
 
 #include "gpu/command_buffer/client/cmd_buffer_helper.h"
 
 #include "base/logging.h"
 #include "gpu/command_buffer/common/command_buffer.h"
@@ skipping 87 matching lines @@
   scoped_refptr<Buffer> buffer =
       command_buffer_->CreateTransferBuffer(ring_buffer_size_, &id);
   if (id < 0) {
     ClearUsable();
     return false;
   }
 
   ring_buffer_ = buffer;
   ring_buffer_id_ = id;
   command_buffer_->SetGetBuffer(id);
-
-  // TODO(gman): Do we really need to call GetState here? We know get & put = 0
-  // Also do we need to check state.num_entries?
-  CommandBuffer::State state = command_buffer_->GetState();
   entries_ = static_cast<CommandBufferEntry*>(ring_buffer_->memory());
-  int32 num_ring_buffer_entries =
-      ring_buffer_size_ / sizeof(CommandBufferEntry);
-  if (num_ring_buffer_entries > state.num_entries) {
-    ClearUsable();
-    return false;
-  }
-
-  total_entry_count_ = num_ring_buffer_entries;
-  put_ = state.put_offset;
+  total_entry_count_ = ring_buffer_size_ / sizeof(CommandBufferEntry);
+  // Call to SetGetBuffer(id) above resets get and put offsets to 0.
+  // No need to query it through IPC.
+  put_ = 0;
   CalcImmediateEntries(0);
   return true;
 }
 
 void CommandBufferHelper::FreeResources() {
   if (HaveRingBuffer()) {
     command_buffer_->DestroyTransferBuffer(ring_buffer_id_);
     ring_buffer_id_ = -1;
     CalcImmediateEntries(0);
   }
@@ skipping 159 matching lines @@
       if (!WaitForGetOffsetInRange(put_ + count + 1, put_))
         return;
       CalcImmediateEntries(count);
       DCHECK_GE(immediate_entry_count_, count);
     }
   }
 }
 
 
 }  // namespace gpu