Fix clang-tidy warnings in camera.

* Add explicit keyword to conversion constructors.
Bug: 28341362
* Use const reference type for read-only parameters.
Bug: 30407689
* Use const reference type to avoid unnecessary copy.
Bug: 30413862
Test: build with WITH_TIDY=1

Change-Id: I71d3008da843ba5f1df1a73a320fb2af6ceffa16
diff --git a/services/camera/libcameraservice/common/Camera2ClientBase.h b/services/camera/libcameraservice/common/Camera2ClientBase.h
index 4f60034..dbbf638 100644
--- a/services/camera/libcameraservice/common/Camera2ClientBase.h
+++ b/services/camera/libcameraservice/common/Camera2ClientBase.h
@@ -93,13 +93,13 @@
       public:
         class Lock {
           public:
-            Lock(SharedCameraCallbacks &client);
+            explicit Lock(SharedCameraCallbacks &client);
             ~Lock();
             sp<TCamCallbacks> &mRemoteCallback;
           private:
             SharedCameraCallbacks &mSharedClient;
         };
-        SharedCameraCallbacks(const sp<TCamCallbacks>& client);
+        explicit SharedCameraCallbacks(const sp<TCamCallbacks>& client);
         SharedCameraCallbacks& operator=(const sp<TCamCallbacks>& client);
         void clear();
       private: