Implement instanced rendering for simple shapes

src/gpu/GrDrawTarget.cpp

Index: src/gpu/GrDrawTarget.cpp
diff --git a/src/gpu/GrDrawTarget.cpp b/src/gpu/GrDrawTarget.cpp
index 49c46feeaf62e390b91ccb21d9a3f6e8e0dce243..0a518bbcbb1777e71342253e8b9033a295f12aa5 100644
--- a/src/gpu/GrDrawTarget.cpp
+++ b/src/gpu/GrDrawTarget.cpp
@@ -16,6 +16,7 @@
 #include "GrRenderTarget.h"
 #include "GrResourceProvider.h"
 #include "GrRenderTargetPriv.h"
+#include "GrInstancedRendering.h"
 #include "GrSurfacePriv.h"
 #include "GrTexture.h"
 #include "gl/GrGLRenderTarget.h"
@@ -42,7 +43,8 @@ GrDrawTarget::GrDrawTarget(GrRenderTarget* rt, GrGpu* gpu, GrResourceProvider* r
     , fResourceProvider(resourceProvider)
     , fAuditTrail(auditTrail)
     , fFlags(0)
-    , fRenderTarget(rt) {
+    , fRenderTarget(rt)
+    , fInstancedRendering(fGpu->createInstancedRenderingIfSupported()) {
     // TODO: Stop extracting the context (currently needed by GrClipMaskManager)
     fContext = fGpu->getContext();
     fClipMaskManager.reset(new GrClipMaskManager(this, options.fClipBatchToBounds));
@@ -202,6 +204,10 @@ void GrDrawTarget::prepareBatches(GrBatchFlushState* flushState) {
             fBatches[i]->prepare(flushState);
         }
     }
+
+    if (fInstancedRendering) {
+        fInstancedRendering->beginFlush(flushState->resourceProvider());
+    }
 }
 
 void GrDrawTarget::drawBatches(GrBatchFlushState* flushState) {
@@ -229,6 +235,9 @@ void GrDrawTarget::drawBatches(GrBatchFlushState* flushState) {
 
 void GrDrawTarget::reset() {
     fBatches.reset();
+    if (fInstancedRendering) {
+        fInstancedRendering->endFlush();
+    }
 }
 
 void GrDrawTarget::drawBatch(const GrPipelineBuilder& pipelineBuilder,