[inspector] introduced stepIntoAsync for chained callbacks

src/inspector/v8-debugger-agent-impl.cc

 // Copyright 2015 the V8 project authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "src/inspector/v8-debugger-agent-impl.h"
 
 #include <algorithm>
 
 #include "src/debug/debug-interface.h"
 #include "src/inspector/injected-script.h"
@@ skipping 440 matching lines @@
       itStartRange, ranges.end(),
       std::make_pair(end.GetLineNumber(), end.GetColumnNumber()),
       positionComparator);
   // Ranges array contains positions in script where blackbox state is changed.
   // [(0,0) ... ranges[0]) isn't blackboxed, [ranges[0] ... ranges[1]) is
   // blackboxed...
   return itStartRange == itEndRange &&
          std::distance(ranges.begin(), itStartRange) % 2;
 }
 
+void V8DebuggerAgentImpl::asyncTaskCreated() {
+  if (m_scheduledDebuggerStep == StepInto) {
+    breakProgram(protocol::Debugger::Paused::ReasonEnum::CallbackScheduled,
+                 nullptr);
+  }
+}
+
+Response V8DebuggerAgentImpl::stepIntoAsync() {
+  return m_debugger->stepIntoAsync();
+}
+
+void V8DebuggerAgentImpl::asyncTaskStarted() {
+  schedulePauseOnNextStatement(protocol::Debugger::Paused::ReasonEnum::Other,
+                               nullptr);
+}
+
+void V8DebuggerAgentImpl::asyncTaskFinished() { cancelPauseOnNextStatement(); }
+
 std::unique_ptr<protocol::Debugger::Location>
 V8DebuggerAgentImpl::resolveBreakpoint(const String16& breakpointId,
                                        const ScriptBreakpoint& breakpoint,
                                        BreakpointSource source) {
   v8::HandleScope handles(m_isolate);
   DCHECK(enabled());
   // FIXME: remove these checks once crbug.com/520702 is resolved.
   CHECK(!breakpointId.isEmpty());
   CHECK(!breakpoint.script_id.isEmpty());
   ScriptsMap::iterator scriptIterator = m_scripts.find(breakpoint.script_id);
@@ skipping 715 matching lines @@
 void V8DebuggerAgentImpl::reset() {
   if (!enabled()) return;
   m_scheduledDebuggerStep = NoStep;
   m_blackboxedPositions.clear();
   resetBlackboxedStateCache();
   m_scripts.clear();
   m_breakpointIdToDebuggerBreakpointIds.clear();
 }
 
 }  // namespace v8_inspector