Fix google-explicit-constructor warnings.

Bug: 28341362
Change-Id: I080090d50f1a368a4e7c1a0732297bb6a295e34f
diff --git a/tools/aapt/Command.cpp b/tools/aapt/Command.cpp
index 9976d00..447ace6 100644
--- a/tools/aapt/Command.cpp
+++ b/tools/aapt/Command.cpp
@@ -494,7 +494,7 @@
 
 struct Feature {
     Feature() : required(false), version(-1) {}
-    Feature(bool required, int32_t version = -1) : required(required), version(version) {}
+    explicit Feature(bool required, int32_t version = -1) : required(required), version(version) {}
 
     /**
      * Whether the feature is required.
diff --git a/tools/aapt2/compile/XmlIdCollector.cpp b/tools/aapt2/compile/XmlIdCollector.cpp
index f40689e..9fc979c 100644
--- a/tools/aapt2/compile/XmlIdCollector.cpp
+++ b/tools/aapt2/compile/XmlIdCollector.cpp
@@ -35,7 +35,7 @@
 
     std::vector<SourcedResourceName>* mOutSymbols;
 
-    IdCollector(std::vector<SourcedResourceName>* outSymbols) : mOutSymbols(outSymbols) {
+    explicit IdCollector(std::vector<SourcedResourceName>* outSymbols) : mOutSymbols(outSymbols) {
     }
 
     void visit(xml::Element* element) override {
diff --git a/tools/aapt2/link/ManifestFixer.cpp b/tools/aapt2/link/ManifestFixer.cpp
index 953e87e..4d8c5fb 100644
--- a/tools/aapt2/link/ManifestFixer.cpp
+++ b/tools/aapt2/link/ManifestFixer.cpp
@@ -220,7 +220,7 @@
 public:
     using xml::Visitor::visit;
 
-    FullyQualifiedClassNameVisitor(const StringPiece16& package) : mPackage(package) {
+    explicit FullyQualifiedClassNameVisitor(const StringPiece16& package) : mPackage(package) {
     }
 
     void visit(xml::Element* el) override {
diff --git a/tools/aapt2/proto/TableProtoDeserializer.cpp b/tools/aapt2/proto/TableProtoDeserializer.cpp
index 82e4fb0..6489b86 100644
--- a/tools/aapt2/proto/TableProtoDeserializer.cpp
+++ b/tools/aapt2/proto/TableProtoDeserializer.cpp
@@ -30,7 +30,7 @@
 public:
     using ValueVisitor::visit;
 
-    ReferenceIdToNameVisitor(const std::map<ResourceId, ResourceNameRef>* mapping) :
+    explicit ReferenceIdToNameVisitor(const std::map<ResourceId, ResourceNameRef>* mapping) :
             mMapping(mapping) {
         assert(mMapping);
     }
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);
diff --git a/tools/aapt2/unflatten/BinaryResourceParser.cpp b/tools/aapt2/unflatten/BinaryResourceParser.cpp
index ec46751..5cd1c8b 100644
--- a/tools/aapt2/unflatten/BinaryResourceParser.cpp
+++ b/tools/aapt2/unflatten/BinaryResourceParser.cpp
@@ -47,7 +47,7 @@
 public:
     using ValueVisitor::visit;
 
-    ReferenceIdToNameVisitor(const std::map<ResourceId, ResourceName>* mapping) :
+    explicit ReferenceIdToNameVisitor(const std::map<ResourceId, ResourceName>* mapping) :
             mMapping(mapping) {
         assert(mMapping);
     }