Add InputDevice stats atom logging

Logging InputDevice information with Android stats atom, when an
InputDevice is added to inputflinger.

Bug: 170321221
Test: Manual test: m statsd_testdrive, statsd_testdrive id
Change-Id: I484fd0a487b35c1946ee7db6ff0f70a92168b6bd
diff --git a/libs/input/tests/Flags_test.cpp b/libs/input/tests/Flags_test.cpp
index 0dbb4cf..6de030f 100644
--- a/libs/input/tests/Flags_test.cpp
+++ b/libs/input/tests/Flags_test.cpp
@@ -148,6 +148,11 @@
     ASSERT_NE(flags1, flags2);
 }
 
+TEST(Flags, GetValue) {
+    Flags<TestFlags> flags = TestFlags::ONE | TestFlags::TWO;
+    ASSERT_EQ(flags.get(), 0x3);
+}
+
 TEST(Flags, String_NoFlags) {
     Flags<TestFlags> flags;
     ASSERT_EQ(flags.string(), "0x0");