Add "Available since" text to all android/ headers.

Also fix a few missing/incorrect annotations.

Bug: http://b/143470841
Test: treehugger
Change-Id: I1d9ec8350df03df7d80f1cc2334eef45deec30ec
diff --git a/include/android/native_window_jni.h b/include/android/native_window_jni.h
index 0c196b9..3a77ffe 100644
--- a/include/android/native_window_jni.h
+++ b/include/android/native_window_jni.h
@@ -51,6 +51,8 @@
  * the ANativeWindow; maintains it through general Java object's life cycle;
  * and will automatically release the reference when the Java object gets garbage
  * collected.
+ *
+ * Available since API level 26.
  */
 jobject ANativeWindow_toSurface(JNIEnv* env, ANativeWindow* window) __INTRODUCED_IN(26);
 #endif