Revert of Move instanced index buffer creation to flush time

src/gpu/GrGpu.cpp

Index: src/gpu/GrGpu.cpp
diff --git a/src/gpu/GrGpu.cpp b/src/gpu/GrGpu.cpp
index cdf5226ed1f4c8418f7748efbe022e3c1dcb4090..fdb098a637f7f62d2eda9fa75a86b6c8cab26b0e 100644
--- a/src/gpu/GrGpu.cpp
+++ b/src/gpu/GrGpu.cpp
@@ -24,11 +24,14 @@
 GrGpu::GrGpu(GrContext* context)
     : fResetTimestamp(kExpiredTimestamp+1)
     , fResetBits(kAll_GrBackendState)
+    , fQuadIndexBuffer(NULL)
     , fGpuTraceMarkerCount(0)
     , fContext(context) {
 }
 
-GrGpu::~GrGpu() {}
+GrGpu::~GrGpu() {
+    SkSafeSetNull(fQuadIndexBuffer);
+}
 
 void GrGpu::contextAbandoned() {}
 
@@ -181,6 +184,39 @@
     return this->onCreateIndexBuffer(size, dynamic);
 }
 
+GrIndexBuffer* GrGpu::createInstancedIndexBuffer(const uint16_t* pattern,
+                                                 int patternSize,
+                                                 int reps,
+                                                 int vertCount,
+                                                 bool isDynamic) {
+    size_t bufferSize = patternSize * reps * sizeof(uint16_t);
+    GrGpu* me = const_cast<GrGpu*>(this);
+    GrIndexBuffer* buffer = me->createIndexBuffer(bufferSize, isDynamic);
+    if (buffer) {
+        uint16_t* data = (uint16_t*) buffer->map();
+        bool useTempData = (NULL == data);
+        if (useTempData) {
+            data = SkNEW_ARRAY(uint16_t, reps * patternSize);
+        }
+        for (int i = 0; i < reps; ++i) {
+            int baseIdx = i * patternSize;
+            uint16_t baseVert = (uint16_t)(i * vertCount);
+            for (int j = 0; j < patternSize; ++j) {
+                data[baseIdx+j] = baseVert + pattern[j];
+            }
+        }
+        if (useTempData) {
+            if (!buffer->updateData(data, bufferSize)) {
+                SkFAIL("Can't get indices into buffer!");
+            }
+            SkDELETE_ARRAY(data);
+        } else {
+            buffer->unmap();
+        }
+    }
+    return buffer;
+}
+
 void GrGpu::clear(const SkIRect* rect,
                   GrColor color,
                   bool canIgnoreRect,
@@ -265,6 +301,29 @@
         this->didRemoveGpuTraceMarker();
         --fGpuTraceMarkerCount;
     }
+}
+
+////////////////////////////////////////////////////////////////////////////////
+
+static const int MAX_QUADS = 1 << 12; // max possible: (1 << 14) - 1;
+
+GR_STATIC_ASSERT(4 * MAX_QUADS <= 65535);
+
+static const uint16_t gQuadIndexPattern[] = {
+  0, 1, 2, 0, 2, 3
+};
+
+const GrIndexBuffer* GrGpu::getQuadIndexBuffer() const {
+    if (NULL == fQuadIndexBuffer || fQuadIndexBuffer->wasDestroyed()) {
+        SkSafeUnref(fQuadIndexBuffer);
+        GrGpu* me = const_cast<GrGpu*>(this);
+        fQuadIndexBuffer = me->createInstancedIndexBuffer(gQuadIndexPattern,
+                                                          6,
+                                                          MAX_QUADS,
+                                                          4);
+    }
+
+    return fQuadIndexBuffer;
 }
 
 ////////////////////////////////////////////////////////////////////////////////