Attempt to combine batches in forward direction before flush

src/gpu/GrContext.cpp

Index: src/gpu/GrContext.cpp
diff --git a/src/gpu/GrContext.cpp b/src/gpu/GrContext.cpp
index 8844f1ac838a887ce2a437b49e55cd7f6abc70e0..a16d5c009a8457c2f5d266c342f528cc74181ab6 100644
--- a/src/gpu/GrContext.cpp
+++ b/src/gpu/GrContext.cpp
@@ -95,6 +95,7 @@ void GrContext::initCommon(const GrContextOptions& options) {
     dtOptions.fClipBatchToBounds = options.fClipBatchToBounds;
     dtOptions.fDrawBatchBounds = options.fDrawBatchBounds;
     dtOptions.fMaxBatchLookback = options.fMaxBatchLookback;
+    dtOptions.fMaxBatchLookahead = options.fMaxBatchLookahead;
     fDrawingManager.reset(new GrDrawingManager(this, dtOptions, &fSingleOwner));
 
     // GrBatchFontCache will eventually replace GrFontCache