Prototype: NativeLayer renderer with GL fallback

cc/output/renderer_chain.cc

Index: cc/output/renderer_chain.cc
diff --git a/cc/output/renderer_chain.cc b/cc/output/renderer_chain.cc
new file mode 100644
index 0000000000000000000000000000000000000000..8509f0834b338f2080deeef64624c5ca254ec189
--- /dev/null
+++ b/cc/output/renderer_chain.cc
@@ -0,0 +1,60 @@
+// Copyright 2015 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#include "cc/output/renderer_chain.h"
+
+namespace cc {
+
+scoped_ptr<RendererChain> RendererChain::Create() {
+  return make_scoped_ptr(new RendererChain());
+}
+
+RendererChain::RendererChain()
+    : Renderer(nullptr, nullptr), active_renderer_(nullptr) {}
+
+RendererChain::~RendererChain() {}
+
+void RendererChain::AddRenderer(scoped_ptr<Renderer> renderer) {
+  renderers_.push_back(renderer.Pass());
+}
+
+const RendererCapabilitiesImpl& RendererChain::Capabilities() const {
+  return renderers_.back()->Capabilities();
+}
+
+void RendererChain::DecideRenderPassAllocationsForFrame(
+    const RenderPassList& render_passes) {
+  active_renderer_ = nullptr;
+  for (auto renderer : renderers_) {
+    if (renderer->CanRender(render_passes)) {
+      active_renderer_ = renderer;
+      break;
+    }
+  }
+  active_renderer_->DecideRenderPassAllocationsForFrame(render_passes);
+}
+
+void RendererChain::DrawFrame(RenderPassList* render_passes,
+                              float scale_factor,
+                              const gfx::Rect& viewport_rect,
+                              const gfx::Rect& clip_rect,
+                              bool disable_picture_quad_image_filtering) {
+  active_renderer_->DrawFrame(render_passes, scale_factor, viewport_rect,
+                              clip_rect, disable_picture_quad_image_filtering);
+}
+
+void RendererChain::SwapBuffers(const CompositorFrameMetadata& metadata) {
+  active_renderer_->SwapBuffers(metadata);
+}
+
+void RendererChain::Finish() {
+  active_renderer_->Finish();
+}
+
+void RendererChain::DidChangeVisibility() {
+  for (auto renderer : renderers_)
+    renderer->SetVisible(visible());
+}
+
+}  // namespace cc