Run clang-tidy modernize-use-equals-{delete,default} on //base

See the bugs and cxx post for justification and details:
https://groups.google.com/a/chromium.org/forum/#!topic/cxx/RkOHzIK6Tq8

This change was done using clang-tidy as described here:
https://chromium.googlesource.com/chromium/src/+/lkcr/docs/clang_tidy.md

In some cases the the tool leaves behind a string of commas where it
replaced a member initializer list
(https://bugs.llvm.org/show_bug.cgi?id=35051). They were cleaned up with:
  git diff --name-only | \
    xargs sed -E -i 's/(^\s*|\)\s*):[ ,]*= default/\1 = default/'

BUG=778959,778957

Change-Id: I95a3f3dae4796e4a7beb77793a6101f433a2c649
Reviewed-on: https://chromium-review.googlesource.com/789718
Reviewed-by: Daniel Cheng <[email protected]>
Commit-Queue: Chris Watkins <[email protected]>
Cr-Commit-Position: refs/heads/master@{#520033}
diff --git a/base/memory/ref_counted_unittest.cc b/base/memory/ref_counted_unittest.cc
index afaebdb..96f588e6 100644
--- a/base/memory/ref_counted_unittest.cc
+++ b/base/memory/ref_counted_unittest.cc
@@ -14,7 +14,7 @@
 
 class SelfAssign : public base::RefCounted<SelfAssign> {
  protected:
-  virtual ~SelfAssign() {}
+  virtual ~SelfAssign() = default;
 
  private:
   friend class base::RefCounted<SelfAssign>;
@@ -22,7 +22,7 @@
 
 class Derived : public SelfAssign {
  protected:
-  ~Derived() override {}
+  ~Derived() override = default;
 
  private:
   friend class base::RefCounted<Derived>;
@@ -112,7 +112,7 @@
  private:
   friend class base::RefCounted<Other>;
 
-  ~Other() {}
+  ~Other() = default;
 };
 
 class HasPrivateDestructorWithDeleter;
@@ -124,11 +124,11 @@
 class HasPrivateDestructorWithDeleter
     : public base::RefCounted<HasPrivateDestructorWithDeleter, Deleter> {
  public:
-  HasPrivateDestructorWithDeleter() {}
+  HasPrivateDestructorWithDeleter() = default;
 
  private:
   friend struct Deleter;
-  ~HasPrivateDestructorWithDeleter() {}
+  ~HasPrivateDestructorWithDeleter() = default;
 };
 
 void Deleter::Destruct(const HasPrivateDestructorWithDeleter* x) {
@@ -147,11 +147,11 @@
  public:
   REQUIRE_ADOPTION_FOR_REFCOUNTED_TYPE();
 
-  InitialRefCountIsOne() {}
+  InitialRefCountIsOne() = default;
 
  private:
   friend class base::RefCounted<InitialRefCountIsOne>;
-  ~InitialRefCountIsOne() {}
+  ~InitialRefCountIsOne() = default;
 };
 
 }  // end namespace