added support for PLS path rendering

src/gpu/GrGpu.cpp

Index: src/gpu/GrGpu.cpp
diff --git a/src/gpu/GrGpu.cpp b/src/gpu/GrGpu.cpp
index 43a75ae56759b928d66382b7479973dba7f40f58..ab8e5cb5359a4e025f748a89a0db69fc365c6313 100644
--- a/src/gpu/GrGpu.cpp
+++ b/src/gpu/GrGpu.cpp
@@ -366,6 +366,9 @@ void GrGpu::resolveRenderTarget(GrRenderTarget* target) {
     this->onResolveRenderTarget(target);
 }
 
+void GrGpu::performFlushWorkaround() {
+}
+
 ////////////////////////////////////////////////////////////////////////////////
 
 void GrGpu::draw(const DrawArgs& args, const GrVertices& vertices) {
@@ -381,3 +384,4 @@ void GrGpu::draw(const DrawArgs& args, const GrVertices& vertices) {
         fStats.incNumDraws();
     } while ((verts = iter.next()));
 }
+