Implement runtime switch to select default renderer mode

Add a system property debug.hwui.default_renderer, which allows
to set rendering mode to OpenGL (default), Skia OpenGL or Vulkan.

Change-Id: I8bca5bacc5108f77437e340ac61f2d8db8cc4c39
diff --git a/libs/hwui/renderthread/CanvasContext.cpp b/libs/hwui/renderthread/CanvasContext.cpp
index 0a48a0c..582c3ea 100644
--- a/libs/hwui/renderthread/CanvasContext.cpp
+++ b/libs/hwui/renderthread/CanvasContext.cpp
@@ -61,6 +61,28 @@
 namespace uirenderer {
 namespace renderthread {
 
+CanvasContext* CanvasContext::create(RenderThread& thread,
+        bool translucent, RenderNode* rootRenderNode, IContextFactory* contextFactory) {
+
+    auto renderType = Properties::getRenderPipelineType();
+    switch (renderType) {
+        case RenderPipelineType::OpenGL:
+            return new CanvasContext(thread, translucent, rootRenderNode, contextFactory);
+        case RenderPipelineType::SkiaGL:
+            //TODO: implement SKIA GL
+            LOG_ALWAYS_FATAL("skiaGL canvas type not implemented.");
+            break;
+        case RenderPipelineType::Vulkan:
+            //TODO: implement Vulkan
+            LOG_ALWAYS_FATAL("Vulkan canvas type not implemented.");
+            break;
+        default:
+            LOG_ALWAYS_FATAL("canvas context type %d not supported", (int32_t) renderType);
+            break;
+    }
+    return nullptr;
+}
+
 CanvasContext::CanvasContext(RenderThread& thread, bool translucent,
         RenderNode* rootRenderNode, IContextFactory* contextFactory)
         : mRenderThread(thread)
@@ -789,6 +811,11 @@
     return mFrameNumber;
 }
 
+bool CanvasContext::isSkiaEnabled() {
+    auto renderType = Properties::getRenderPipelineType();
+    return RenderPipelineType::SkiaGL == renderType || RenderPipelineType::Vulkan == renderType;
+}
+
 } /* namespace renderthread */
 } /* namespace uirenderer */
 } /* namespace android */