sdk: Add example code

Add SDK example code imported from https://github.com/skyostil/perfetto-sdk-example

Change-Id: Ic3a478091575d7129e39114d4b0c4280137b5f40
diff --git a/docs/instrumentation/tracing-sdk.md b/docs/instrumentation/tracing-sdk.md
index 1c88946..f156bcf 100644
--- a/docs/instrumentation/tracing-sdk.md
+++ b/docs/instrumentation/tracing-sdk.md
@@ -24,8 +24,8 @@
 
 ## Getting started
 
-TIP: The code from these examples is also available as a
-[GitHub repository](https://github.com/skyostil/perfetto-sdk-example).
+TIP: The code from these examples is also available [in the
+repository](../../examples/sdk/README.md).
 
 To start using the Client API, first check out the latest SDK release: