cc: Add a flag to check for tile priority inversion in AssignGpuMemory.

cc/base/switches.cc

Index: cc/base/switches.cc
diff --git a/cc/base/switches.cc b/cc/base/switches.cc
index 94890bdfdf6b9751ba9c5af9ec7f3f7129fb219e..b7de4724ccefc1a8be3b44965956528779bfcd78 100644
--- a/cc/base/switches.cc
+++ b/cc/base/switches.cc
@@ -57,6 +57,9 @@ const char kEnableGpuBenchmarking[] = "enable-gpu-benchmarking";
 // with physically correct blending and interpolation.
 const char kEnableTrueColorRendering[] = "enable-true-color-rendering";
 
+// Enables CHECKs to ensure that tile priorities are not inverted.
+const char kCheckTilePriorityInversion[] = "check-tile-priority-inversion";
+
 // Renders a border around compositor layers to help debug and study
 // layer compositing.
 const char kShowCompositedLayerBorders[] = "show-composited-layer-borders";