Remove transitional explicit operator bool.

include/core/SkRefCnt.h

 /*
  * Copyright 2006 The Android Open Source Project
  *
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file.
  */
 
 #ifndef SkRefCnt_DEFINED
 #define SkRefCnt_DEFINED
 
@@ skipping 182 matching lines @@
 template <typename T> class SkAutoTUnref : public std::unique_ptr<T, SkTUnref<T>> {
 public:
     explicit SkAutoTUnref(T* obj = nullptr) : std::unique_ptr<T, SkTUnref<T>>(obj) {}
 
     operator T*() const { return this->get(); }
 
 #if defined(SK_BUILD_FOR_ANDROID_FRAMEWORK)
     // Need to update graphics/Shader.cpp.
     T* detach() { return this->release(); }
 #endif
-
-    // Android's std::unique_ptr's operator bool() is sometimes not explicit...
-    // so override it with our own explcitly explicit version.
-    explicit operator bool() const { return this->get() != nullptr; }
 };
 // Can't use the #define trick below to guard a bare SkAutoTUnref(...) because it's templated. :(
 
 class SkAutoUnref : public SkAutoTUnref<SkRefCnt> {
 public:
     SkAutoUnref(SkRefCnt* obj) : SkAutoTUnref<SkRefCnt>(obj) {}
 };
 #define SkAutoUnref(...) SK_REQUIRE_LOCAL_VAR(SkAutoUnref)
 
 // This is a variant of SkRefCnt that's Not Virtual, so weighs 4 bytes instead of 8 or 16.
@@ skipping 234 matching lines @@
  *
  *  This function may be helpful while we convert callers from ptr-based to sk_sp-based parameters.
  */
 template <typename T> sk_sp<T> sk_ref_sp(T* obj) {
     return sk_sp<T>(SkSafeRef(obj));
 }
 
 #endif
 
 #endif