Fix google-explicit-constructor warnings.

Bug: 28341362
Change-Id: I080090d50f1a368a4e7c1a0732297bb6a295e34f
diff --git a/tools/aapt2/split/TableSplitter.cpp b/tools/aapt2/split/TableSplitter.cpp
index 4bfdb12..2dfe2a2 100644
--- a/tools/aapt2/split/TableSplitter.cpp
+++ b/tools/aapt2/split/TableSplitter.cpp
@@ -40,7 +40,7 @@
  */
 class SplitValueSelector {
 public:
-    SplitValueSelector(const SplitConstraints& constraints) {
+    explicit SplitValueSelector(const SplitConstraints& constraints) {
         for (const ConfigDescription& config : constraints.configs) {
             if (config.density == 0) {
                 mDensityIndependentConfigs.insert(config);