Implement instanced rendering for simple shapes

src/gpu/gl/GrGLGpu.cpp

Index: src/gpu/gl/GrGLGpu.cpp
diff --git a/src/gpu/gl/GrGLGpu.cpp b/src/gpu/gl/GrGLGpu.cpp
index e50f1e2fdbb50d46c7842891ee6e988ef265c3a1..972bc90bdca735ff2fe106fa8e650396d9a7d2a6 100644
--- a/src/gpu/gl/GrGLGpu.cpp
+++ b/src/gpu/gl/GrGLGpu.cpp
@@ -8,6 +8,7 @@
 #include "GrGLGpu.h"
 #include "GrGLBuffer.h"
 #include "GrGLGLSL.h"
+#include "GrGLInstancedRendering.h"
 #include "GrGLStencilAttachment.h"
 #include "GrGLTextureRenderTarget.h"
 #include "GrGpuResourcePriv.h"
@@ -455,6 +456,10 @@ void GrGLGpu::disconnect(DisconnectType type) {
 
 ///////////////////////////////////////////////////////////////////////////////
 
+GrInstancedRendering* GrGLGpu::createInstancedRenderingIfSupported() {
+    return GrGLInstancedRendering::CreateIfSupported(this);
+}
+
 void GrGLGpu::onResetContext(uint32_t resetBits) {
     // we don't use the zb at all
     if (resetBits & kMisc_GrGLBackendState) {