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/tools_sanity_unittest.cc b/base/tools_sanity_unittest.cc
index af2081d3..5c41bd7 100644
--- a/base/tools_sanity_unittest.cc
+++ b/base/tools_sanity_unittest.cc
@@ -254,7 +254,7 @@
 class TOOLS_SANITY_TEST_CONCURRENT_THREAD : public PlatformThread::Delegate {
  public:
   explicit TOOLS_SANITY_TEST_CONCURRENT_THREAD(bool *value) : value_(value) {}
-  ~TOOLS_SANITY_TEST_CONCURRENT_THREAD() override {}
+  ~TOOLS_SANITY_TEST_CONCURRENT_THREAD() override = default;
   void ThreadMain() override {
     *value_ = true;
 
@@ -270,7 +270,7 @@
 class ReleaseStoreThread : public PlatformThread::Delegate {
  public:
   explicit ReleaseStoreThread(base::subtle::Atomic32 *value) : value_(value) {}
-  ~ReleaseStoreThread() override {}
+  ~ReleaseStoreThread() override = default;
   void ThreadMain() override {
     base::subtle::Release_Store(value_, kMagicValue);
 
@@ -286,7 +286,7 @@
 class AcquireLoadThread : public PlatformThread::Delegate {
  public:
   explicit AcquireLoadThread(base::subtle::Atomic32 *value) : value_(value) {}
-  ~AcquireLoadThread() override {}
+  ~AcquireLoadThread() override = default;
   void ThreadMain() override {
     // Wait for the other thread to make Release_Store
     PlatformThread::Sleep(TimeDelta::FromMilliseconds(100));