Move logging interface out of QPL plugin

Summary:
This is generic enough, even though I strongly dislike the
installing mechanism, but that can be changed later.

Reviewed By: oprisnik

Differential Revision: D14131183

fbshipit-source-id: b75c1e1563ac9371cbc7d28b239c316a0aa1a9dd

android/src/main/java/com/facebook/flipper/perflogger/FlipperPerfLogger.java

@@ -0,0 +1,32 @@
+// Copyright 2004-present Facebook. All Rights Reserved.
+
+package com.facebook.flipper.plugins.qpl.api;
+
+import android.support.annotation.Nullable;
+
+public class FlipperPerfLogger {
+
+  @Nullable private static PerfLoggerDelegate mDelegate;
+
+  public static void startMarker(String name) {
+    if (mDelegate != null) {
+      mDelegate.starMarker(name);
+    }
+  }
+
+  public static void endMarker(String name) {
+    if (mDelegate != null) {
+      mDelegate.endMarker(name);
+    }
+  }
+
+  public static void cancelMarker(String name) {
+    if (mDelegate != null) {
+      mDelegate.cancelMarker(name);
+    }
+  }
+
+  static void setDelegate(PerfLoggerDelegate delegate) {
+    mDelegate = delegate;
+  }
+}

android/src/main/java/com/facebook/flipper/perflogger/PerfLoggerDelegate.java

@@ -0,0 +1,11 @@
+// Copyright 2004-present Facebook. All Rights Reserved.
+
+package com.facebook.flipper.plugins.qpl.api;
+
+public interface PerfLoggerDelegate {
+  void starMarker(String name);
+
+  void endMarker(String name);
+
+  void cancelMarker(String name);
+}

android/src/main/java/com/facebook/flipper/perflogger/PerfLoggerDelegateInstaller.java

@@ -0,0 +1,9 @@
+// Copyright 2004-present Facebook. All Rights Reserved.
+
+package com.facebook.flipper.plugins.qpl.api;
+
+public class PerfLoggerDelegateInstaller {
+  public static void install(PerfLoggerDelegate delegate) {
+    FlipperPerfLogger.setDelegate(delegate);
+  }
+}