WIP GPU scheduler + delayed activation / tile draw

gpu/ipc/common/gpu_stream_constants.h

Index: gpu/ipc/common/gpu_stream_constants.h
diff --git a/gpu/ipc/common/gpu_stream_constants.h b/gpu/ipc/common/gpu_stream_constants.h
index abab39895328ca4a1b09e0726aed23fc02e913d4..bb3ec5b3429eb8ef992aced03632d8b4f738e9b7 100644
--- a/gpu/ipc/common/gpu_stream_constants.h
+++ b/gpu/ipc/common/gpu_stream_constants.h
@@ -5,12 +5,17 @@
 #ifndef GPU_IPC_COMMON_GPU_STREAM_CONSTANTS_H_
 #define GPU_IPC_COMMON_GPU_STREAM_CONSTANTS_H_
 
+#include "gpu/gpu_export.h"
+
 namespace gpu {
 
-enum class GpuStreamPriority { REAL_TIME, HIGH, NORMAL, LOW, LAST = LOW };
+enum class GpuStreamPriority : int { REAL_TIME, HIGH, NORMAL, LOW, LAST = LOW };
+static const int kNumGpuStreamPriorities = 4;
 
 enum GpuStreamId { GPU_STREAM_DEFAULT = -1, GPU_STREAM_INVALID = 0 };
 
+GPU_EXPORT const char* GpuStreamPriorityToString(GpuStreamPriority priority);
+
 }  // namespace gpu
 
 #endif  // GPU_IPC_COMMON_GPU_STREAM_CONSTANTS_H_