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

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
This CL was uploaded by git cl split.

[email protected]

Change-Id: I95be755819bd151634e88ca26016e102d4d02f27
Reviewed-on: https://chromium-review.googlesource.com/799014
Reviewed-by: Bence Béky <[email protected]>
Commit-Queue: Chris Watkins <[email protected]>
Cr-Commit-Position: refs/heads/master@{#521262}
diff --git a/net/log/test_net_log.cc b/net/log/test_net_log.cc
index 8cdccea..36ef00d 100644
--- a/net/log/test_net_log.cc
+++ b/net/log/test_net_log.cc
@@ -18,8 +18,8 @@
 // that saves messages to a buffer.
 class TestNetLog::Observer : public NetLog::ThreadSafeObserver {
  public:
-  Observer() {}
-  ~Observer() override {}
+  Observer() = default;
+  ~Observer() override = default;
 
   // Returns the list of all entries in the log.
   void GetEntries(TestNetLogEntry::List* entry_list) const {
@@ -110,8 +110,7 @@
     : net_log_(NetLogWithSource::Make(&test_net_log_, NetLogSourceType::NONE)) {
 }
 
-BoundTestNetLog::~BoundTestNetLog() {
-}
+BoundTestNetLog::~BoundTestNetLog() = default;
 
 void BoundTestNetLog::GetEntries(TestNetLogEntry::List* entry_list) const {
   test_net_log_.GetEntries(entry_list);