Skip batch iteration in GrDrawTarget::forwardCombine when the max look ahead is 0

src/gpu/GrDrawTarget.cpp

Index: src/gpu/GrDrawTarget.cpp
diff --git a/src/gpu/GrDrawTarget.cpp b/src/gpu/GrDrawTarget.cpp
index 1889b87133dc5fa1719442df80a2bb84bbc6e308..dc2fd3086121761bc96f7b57ea5f2d059ac7e805 100644
--- a/src/gpu/GrDrawTarget.cpp
+++ b/src/gpu/GrDrawTarget.cpp
@@ -571,6 +571,9 @@ GrBatch* GrDrawTarget::recordBatch(GrBatch* batch, const SkRect& clippedBounds)
 }
 
 void GrDrawTarget::forwardCombine() {
+    if (fMaxBatchLookahead <= 0) {
+        return;
+    }
     for (int i = 0; i < fRecordedBatches.count() - 2; ++i) {
         GrBatch* batch = fRecordedBatches[i].fBatch.get();
         const SkRect& batchBounds = fRecordedBatches[i].fClippedBounds;