Break Layer class into Gl and Vulkan subclasses

Test: manual testing
Change-Id: Ibd2beed39de3ac6da7448e96496253cfe427dfbb
diff --git a/libs/hwui/GlLayer.cpp b/libs/hwui/GlLayer.cpp
new file mode 100644
index 0000000..c0ab895
--- /dev/null
+++ b/libs/hwui/GlLayer.cpp
@@ -0,0 +1,76 @@
+/*
+ * 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 "GlLayer.h"
+
+#include "Caches.h"
+#include "RenderNode.h"
+#include "renderstate/RenderState.h"
+#include "utils/TraceUtils.h"
+
+#include <utils/Log.h>
+
+#define ATRACE_LAYER_WORK(label) \
+    ATRACE_FORMAT("%s HW Layer DisplayList %s %ux%u", \
+            label, \
+            (renderNode.get() != NULL) ? renderNode->getName() : "", \
+            getWidth(), getHeight())
+
+namespace android {
+namespace uirenderer {
+
+GlLayer::GlLayer(RenderState& renderState, uint32_t layerWidth, uint32_t layerHeight)
+        : Layer(renderState, Api::OpenGL)
+        , caches(Caches::getInstance())
+        , texture(caches) {
+    texture.mWidth = layerWidth;
+    texture.mHeight = layerHeight;
+}
+
+GlLayer::~GlLayer() {
+    if (texture.mId) {
+        texture.deleteTexture();
+    }
+}
+
+void GlLayer::onGlContextLost() {
+    texture.deleteTexture();
+}
+
+void GlLayer::bindTexture() const {
+    if (texture.mId) {
+        caches.textureState().bindTexture(texture.target(), texture.mId);
+    }
+}
+
+void GlLayer::generateTexture() {
+    if (!texture.mId) {
+        glGenTextures(1, &texture.mId);
+    }
+}
+
+void GlLayer::clearTexture() {
+    // There's a rare possibility that Caches could have been destroyed already
+    // since this method is queued up as a task.
+    // Since this is a reset method, treat this as non-fatal.
+    if (caches.isInitialized()) {
+        caches.textureState().unbindTexture(texture.mId);
+    }
+    texture.mId = 0;
+}
+
+}; // namespace uirenderer
+}; // namespace android