Fix google-explicit-constructor warnings.

Bug: 28341362
Change-Id: I080090d50f1a368a4e7c1a0732297bb6a295e34f
diff --git a/libs/hwui/tests/unit/FrameBuilderTests.cpp b/libs/hwui/tests/unit/FrameBuilderTests.cpp
index 0f16b15..103f156 100644
--- a/libs/hwui/tests/unit/FrameBuilderTests.cpp
+++ b/libs/hwui/tests/unit/FrameBuilderTests.cpp
@@ -1919,7 +1919,7 @@
         std::function<void(const RectOp&, const BakedOpState&)> opValidateCallback) {
     class PropertyTestRenderer : public TestRendererBase {
     public:
-        PropertyTestRenderer(std::function<void(const RectOp&, const BakedOpState&)> callback)
+        explicit PropertyTestRenderer(std::function<void(const RectOp&, const BakedOpState&)> callback)
                 : mCallback(callback) {}
         void onRectOp(const RectOp& op, const BakedOpState& state) override {
             EXPECT_EQ(mIndex++, 0);
@@ -2040,7 +2040,7 @@
         std::function<void(RenderProperties&)> propSetupCallback) {
     class SaveLayerAlphaClipTestRenderer : public TestRendererBase {
     public:
-        SaveLayerAlphaClipTestRenderer(SaveLayerAlphaData* outData)
+        explicit SaveLayerAlphaClipTestRenderer(SaveLayerAlphaData* outData)
                 : mOutData(outData) {}
 
         OffscreenBuffer* startTemporaryLayer(uint32_t width, uint32_t height) override {