New API for computing optimization invariants.

Review URL: https://codereview.chromium.org/1467553002
diff --git a/src/gpu/GrPrimitiveProcessor.h b/src/gpu/GrPrimitiveProcessor.h
index 46136f0..467200a 100644
--- a/src/gpu/GrPrimitiveProcessor.h
+++ b/src/gpu/GrPrimitiveProcessor.h
@@ -56,7 +56,7 @@
  * computed optimizations. It is the batch-specific optimizations that allow the pipelines
  * to be equal.
  */
-class GrPipelineOptimizations {
+class GrXPOverridesForBatch {
 public:
     /** Does the pipeline require the GrPrimitiveProcessor's color? */
     bool readsColor() const { return SkToBool(kReadsColor_Flag & fFlags); }