Add support for dummy draws for Vulkan webview and texture views.

Test: manual testing
Change-Id: Iaec8c3a34367673c281665ff6c6e97d1ce532265
diff --git a/libs/hwui/VkLayer.cpp b/libs/hwui/VkLayer.cpp
new file mode 100644
index 0000000..391acf1
--- /dev/null
+++ b/libs/hwui/VkLayer.cpp
@@ -0,0 +1,40 @@
+/*
+ * Copyright (C) 2017 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#include "VkLayer.h"
+
+#include "renderstate/RenderState.h"
+
+#include <SkCanvas.h>
+#include <SkSurface.h>
+
+namespace android {
+namespace uirenderer {
+
+void VkLayer::updateTexture() {
+    sk_sp<SkSurface> surface;
+    SkImageInfo info = SkImageInfo::MakeS32(mWidth, mHeight, kPremul_SkAlphaType);
+    surface = SkSurface::MakeRenderTarget(mRenderState.getGrContext(), SkBudgeted::kNo, info);
+    surface->getCanvas()->clear(SK_ColorBLUE);
+    mImage = surface->makeImageSnapshot(SkBudgeted::kNo, SkSurface::kNo_ForceUnique);
+}
+
+void VkLayer::onVkContextDestroyed() {
+    mImage = nullptr;
+}
+
+}; // namespace uirenderer
+}; // namespace android