Annotate Files#getNameWithoutExtension as @NotNull

Change-Id: Id55ac3aeaf4de692096b0f0c457ea455220042f4
diff --git a/common/guava-tools/annotations/com/google/common/io/annotations.xml b/common/guava-tools/annotations/com/google/common/io/annotations.xml
new file mode 100644
index 0000000..84dd44b
--- /dev/null
+++ b/common/guava-tools/annotations/com/google/common/io/annotations.xml
@@ -0,0 +1,5 @@
+<root>
+  <item name='com.google.common.io.Files java.lang.String getNameWithoutExtension(java.lang.String)'>
+    <annotation name='org.jetbrains.annotations.NotNull'/>
+  </item>
+</root>
\ No newline at end of file