Adding instrumentation to locate the source of jankiness.

Mechanical change that adds instrumentation required to locate the source of jankiness (i.e. a long-running fragment of code executed as a part of the task that causes jank) in the code. See the bug for details on what kind of jank we are after.
A number of similar CLs were landed, and none of them caused issues. The code of the instrumentation is highly optimized and is not expected to affect performance. The code simply creates a diagnostic task which is identical to ones created by PostTask or IPC message handlers.
Landing as TBR since this is a mechanical, safe and temporary change.

BUG=424386
TBR=rvargas@chromium.org

Review URL: https://codereview.chromium.org/662123002

Cr-Commit-Position: refs/heads/master@{#300163}

net/socket/ssl_client_socket_nss.cc

@@ -1689,6 +1689,11 @@ int SSLClientSocketNSS::Core::HandleNSSError(PRErrorCode nss_error) {
 }
 
 int SSLClientSocketNSS::Core::DoHandshakeLoop(int last_io_result) {
+  // TODO(vadimt): Remove ScopedProfile below once crbug.com/424386 is fixed.
+  tracked_objects::ScopedProfile tracking_profile(
+      FROM_HERE_WITH_EXPLICIT_FUNCTION(
+          "424386 SSLClientSocketNSS::Core::DoHandshakeLoop"));
+
   DCHECK(OnNSSTaskRunner());
 
   int rv = last_io_result;
@@ -1725,6 +1730,11 @@ int SSLClientSocketNSS::Core::DoHandshakeLoop(int last_io_result) {
 }
 
 int SSLClientSocketNSS::Core::DoReadLoop(int result) {
+  // TODO(vadimt): Remove ScopedProfile below once crbug.com/424386 is fixed.
+  tracked_objects::ScopedProfile tracking_profile(
+      FROM_HERE_WITH_EXPLICIT_FUNCTION(
+          "424386 SSLClientSocketNSS::Core::DoReadLoop"));
+
   DCHECK(OnNSSTaskRunner());
   DCHECK(false_started_ || handshake_callback_called_);
   DCHECK_EQ(STATE_NONE, next_handshake_state_);
@@ -2195,6 +2205,11 @@ void SSLClientSocketNSS::Core::OnSendComplete(int result) {
 // callback. For Read() and Write(), that's what we want. But for Connect(),
 // the caller expects OK (i.e. 0) for success.
 void SSLClientSocketNSS::Core::DoConnectCallback(int rv) {
+  // TODO(vadimt): Remove ScopedProfile below once crbug.com/424386 is fixed.
+  tracked_objects::ScopedProfile tracking_profile(
+      FROM_HERE_WITH_EXPLICIT_FUNCTION(
+          "424386 SSLClientSocketNSS::Core::DoConnectCallback"));
+
   DCHECK(OnNSSTaskRunner());
   DCHECK_NE(rv, ERR_IO_PENDING);
   DCHECK(!user_connect_callback_.is_null());
@@ -2206,6 +2221,11 @@ void SSLClientSocketNSS::Core::DoConnectCallback(int rv) {
 }
 
 void SSLClientSocketNSS::Core::DoReadCallback(int rv) {
+  // TODO(vadimt): Remove ScopedProfile below once crbug.com/424386 is fixed.
+  tracked_objects::ScopedProfile tracking_profile(
+      FROM_HERE_WITH_EXPLICIT_FUNCTION(
+          "424386 SSLClientSocketNSS::Core::DoReadCallback"));
+
   DCHECK(OnNSSTaskRunner());
   DCHECK_NE(ERR_IO_PENDING, rv);
   DCHECK(!user_read_callback_.is_null());
@@ -2222,7 +2242,7 @@ void SSLClientSocketNSS::Core::DoReadCallback(int rv) {
       FROM_HERE,
       base::Bind(&Core::DidNSSRead, this, rv));
   // TODO(vadimt): Remove ScopedProfile below once crbug.com/418183 is fixed.
-  tracked_objects::ScopedProfile tracking_profile(
+  tracked_objects::ScopedProfile tracking_profile1(
       FROM_HERE_WITH_EXPLICIT_FUNCTION(
           "SSLClientSocketNSS::Core::DoReadCallback"));
   PostOrRunCallback(