Define global logger instance to be used for all logging

Summary:
The advantage of this is that anyone can now log without needing to carry around a Logger object.
Primary reason is for making metrics less intrusive in the codebase.

Reviewed By: passy

Differential Revision: D13671368

fbshipit-source-id: 162ab1351a124683aef13983fc3bcec01385cd1a

src/dispatcher/androidDevice.js

@@ -81,11 +81,7 @@ export default (store: Store, logger: Logger) => {
       },
     );
   }
-  const clientPromise = recordSuccessMetric(
-    createClient(),
-    'createADBClient',
-    logger,
-  );
+  const clientPromise = recordSuccessMetric(createClient(), 'createADBClient');
 
   const watchAndroidDevices = () => {
     // get emulators