[Impeller] Added a doc page to point out important impeller benchmarks

Author: gaaclarke

impeller/docs/benchmarks.md

@@ -0,0 +1,20 @@
+# Impeller Benchmarks
+
+Here are some noteworthy benchmarks related to Impeller performance:
+
+- **New Gallery** - Runs through the Flutter Gallery with a driver test.
+  - Samsung S10
+    - Vulkan: [skiaperf](https://flutter-flutter-perf.skia.org/e/?keys=X8f96868d3a9eeb120bec1f458c577c30)
+    - OpenGLES: TBD
+    - Vulkan vs OpenGLES: TBD
+  - Moto G4 (OpenGLES): [skiaperf](https://flutter-flutter-perf.skia.org/e/?keys=Xaeae5aa39c9028be43e8a9ad40540bd8)
+  - iPhone 11 (Metal): [skiaperf](https://flutter-flutter-perf.skia.org/e/?keys=Xc30b4774a54a03180fa93bf6641c5469)
+  - Skia vs Vulkan Impeller 90th percentile frame rasterizer time: [skiaperf](https://flutter-flutter-perf.skia.org/e/?keys=X2cacf305c9d4b1b5fc43f81368803a9b)
+
+- **Animated Blur Backdrop Filter** - A driver test that scrolls to a screen and animates a Blur Backdrop filter to get progressively blurrier.
+  - Samsung S10
+    - Vulkan: TBD
+    - OpenGLES: TBD
+    - Vulkan vs OpenGLES: TBD
+  - Moto G4 (OpenGLES): [skiaperf](https://flutter-flutter-perf.skia.org/e/?keys=X78023772ea9e94c81f37456a7fa7bf46)
+  - iPhone 11 (Metal): [skiaperf](https://flutter-flutter-perf.skia.org/e/?keys=X2f7504aba3db6aeff08cc896081ace55)