Add setBackdropRenderEffect for View and RenderNode.

support visual effects for backdrop contents of a View or RenderNode.

Test: added unit test & hwui_unit passes
Test: added BackdropBlurActivity in HwAccelerationTest, build & run it

Signed-off-by: Dongya Jiang <jiangdongya@coolpad.com>
Change-Id: If1ac1b8aee53667f175e8fa80ecfc7bdfa28173d
diff --git a/libs/hwui/Android.bp b/libs/hwui/Android.bp
index db58147..b5e6f94 100644
--- a/libs/hwui/Android.bp
+++ b/libs/hwui/Android.bp
@@ -514,6 +514,7 @@
         "canvas/CanvasOpRasterizer.cpp",
         "effects/StretchEffect.cpp",
         "effects/GainmapRenderer.cpp",
+        "pipeline/skia/BackdropFilterDrawable.cpp",
         "pipeline/skia/HolePunch.cpp",
         "pipeline/skia/SkiaDisplayList.cpp",
         "pipeline/skia/SkiaRecordingCanvas.cpp",