Move statsd metadata from statslog to atoms_info

Clients don't need to know about statsd metadata. Extract out metadata
from statslog.h/cpp into atoms_info.h/cpp which is only used by statsd.

Generated atoms_info.h: https://paste.googleplex.com/6303016724463616
Generated atoms_info.cpp: https://paste.googleplex.com/5717940978581504

Test: m -j
Test: old metadata in statslog matches the metadata in
atoms_info
Test: Flashes successfully
Test: adb logcat "*:S statsd:*"

Change-Id: I56ef3cc4ea1fbd2cd0130d4e9576b242efb9f627
diff --git a/cmds/statsd/Android.bp b/cmds/statsd/Android.bp
index 484f823..afff614 100644
--- a/cmds/statsd/Android.bp
+++ b/cmds/statsd/Android.bp
@@ -146,6 +146,7 @@
         "libprotoutil",
         "libservices",
         "libstatslog",
+        "libstatsmetadata",
         "libstatssocket",
         "libsysutils",
         "libtimestats_proto",
@@ -153,6 +154,63 @@
     ],
 }
 
+// ================
+// libstatsmetadata
+// ================
+
+genrule {
+    name: "atoms_info.h",
+    tools: ["stats-log-api-gen"],
+    cmd: "$(location stats-log-api-gen) --atomsInfoHeader $(genDir)/atoms_info.h",
+    out: [
+        "atoms_info.h",
+    ],
+}
+
+genrule {
+    name: "atoms_info.cpp",
+    tools: ["stats-log-api-gen"],
+    cmd: "$(location stats-log-api-gen) --atomsInfoCpp $(genDir)/atoms_info.cpp",
+    out: [
+        "atoms_info.cpp",
+    ],
+}
+
+cc_library_shared {
+    name: "libstatsmetadata",
+    host_supported: true,
+    generated_sources: [
+        "atoms_info.cpp",
+    ],
+    generated_headers: [
+        "atoms_info.h",
+    ],
+    cflags: [
+        "-Wall",
+        "-Werror",
+    ],
+    export_generated_headers: [
+        "atoms_info.h",
+    ],
+    shared_libs: [
+        "libcutils",
+        "libstatslog",
+    ],
+    target: {
+        android: {
+            shared_libs: [
+                "libutils",
+            ],
+        },
+        host: {
+            static_libs: [
+                "libutils",
+            ],
+        },
+    },
+}
+
+
 // =========
 // statsd
 // =========