Split GrDrawBatch and GrVertexBatch into their own files

TBR=joshualitt@google.com

Review URL: https://codereview.chromium.org/1296483002
diff --git a/src/gpu/batches/GrVertexBatch.cpp b/src/gpu/batches/GrVertexBatch.cpp
new file mode 100644
index 0000000..e800422
--- /dev/null
+++ b/src/gpu/batches/GrVertexBatch.cpp
@@ -0,0 +1,51 @@
+/*
+ * Copyright 2015 Google Inc.
+ *
+ * Use of this source code is governed by a BSD-style license that can be
+ * found in the LICENSE file.
+ */
+
+#include "GrVertexBatch.h"
+#include "GrBatchTarget.h"
+#include "GrResourceProvider.h"
+
+GrVertexBatch::GrVertexBatch() : fNumberOfDraws(0) {}
+
+void* GrVertexBatch::InstancedHelper::init(GrBatchTarget* batchTarget, GrPrimitiveType primType,
+                                     size_t vertexStride, const GrIndexBuffer* indexBuffer,
+                                     int verticesPerInstance, int indicesPerInstance,
+                                     int instancesToDraw) {
+    SkASSERT(batchTarget);
+    if (!indexBuffer) {
+        return NULL;
+    }
+    const GrVertexBuffer* vertexBuffer;
+    int firstVertex;
+    int vertexCount = verticesPerInstance * instancesToDraw;
+    void* vertices = batchTarget->makeVertSpace(vertexStride, vertexCount,
+                                                &vertexBuffer, &firstVertex);
+    if (!vertices) {
+        SkDebugf("Vertices could not be allocated for instanced rendering.");
+        return NULL;
+    }
+    SkASSERT(vertexBuffer);
+    size_t ibSize = indexBuffer->gpuMemorySize();
+    int maxInstancesPerDraw = static_cast<int>(ibSize / (sizeof(uint16_t) * indicesPerInstance));
+
+    fVertices.initInstanced(primType, vertexBuffer, indexBuffer,
+        firstVertex, verticesPerInstance, indicesPerInstance, instancesToDraw,
+        maxInstancesPerDraw);
+    return vertices;
+}
+
+void* GrVertexBatch::QuadHelper::init(GrBatchTarget* batchTarget, size_t vertexStride,
+                                      int quadsToDraw) {
+    SkAutoTUnref<const GrIndexBuffer> quadIndexBuffer(
+        batchTarget->resourceProvider()->refQuadIndexBuffer());
+    if (!quadIndexBuffer) {
+        SkDebugf("Could not get quad index buffer.");
+        return NULL;
+    }
+    return this->INHERITED::init(batchTarget, kTriangles_GrPrimitiveType, vertexStride,
+                                 quadIndexBuffer, kVerticesPerQuad, kIndicesPerQuad, quadsToDraw);
+}