Add function that checks if Matchers A is subset of Matchers B

Test: bit statsd_test:*
Change-Id: I3ee5ff74cf9f79d104e12e555ff417529cf0f915
diff --git a/cmds/statsd/src/FieldValue.cpp b/cmds/statsd/src/FieldValue.cpp
index 84a0607..82e8cd8 100644
--- a/cmds/statsd/src/FieldValue.cpp
+++ b/cmds/statsd/src/FieldValue.cpp
@@ -435,6 +435,25 @@
     return eq;
 }
 
+bool subsetDimensions(const std::vector<Matcher>& dimension_a,
+                      const std::vector<Matcher>& dimension_b) {
+    if (dimension_a.size() > dimension_b.size()) {
+        return false;
+    }
+    for (size_t i = 0; i < dimension_a.size(); ++i) {
+        bool found = false;
+        for (size_t j = 0; j < dimension_b.size(); ++j) {
+            if (dimension_a[i] == dimension_b[j]) {
+                found = true;
+            }
+        }
+        if (!found) {
+            return false;
+        }
+    }
+    return true;
+}
+
 bool HasPositionANY(const FieldMatcher& matcher) {
     if (matcher.has_position() && matcher.position() == Position::ANY) {
         return true;