WIP GPU scheduler + delayed activation / tile draw

gpu/command_buffer/common/command_buffer.h

Index: gpu/command_buffer/common/command_buffer.h
diff --git a/gpu/command_buffer/common/command_buffer.h b/gpu/command_buffer/common/command_buffer.h
index 355c6670217546846093f67030b41e3869730ffb..552444cd3e9f761927919425ebf9187f6d655a9d 100644
--- a/gpu/command_buffer/common/command_buffer.h
+++ b/gpu/command_buffer/common/command_buffer.h
@@ -37,6 +37,8 @@ class GPU_EXPORT CommandBuffer {
     // embedded in the command buffer. The default token value is zero.
     int32_t token;
 
+    uint64_t release_count;
+
     // Error status.
     error::Error error;
 
@@ -94,11 +96,11 @@ class GPU_EXPORT CommandBuffer {
 
   // The writer calls this to wait until the current token is within a
   // specific range, inclusive. Can return early if an error is generated.
-  virtual void WaitForTokenInRange(int32_t start, int32_t end) = 0;
+  virtual State WaitForTokenInRange(int32_t start, int32_t end) = 0;
 
   // The writer calls this to wait until the current get offset is within a
   // specific range, inclusive. Can return early if an error is generated.
-  virtual void WaitForGetOffsetInRange(int32_t start, int32_t end) = 0;
+  virtual State WaitForGetOffsetInRange(int32_t start, int32_t end) = 0;
 
   // Sets the buffer commands are read from.
   // Also resets the get and put offsets to 0.