DevTools: simplify the async instrumentation harness.

third_party/WebKit/Source/platform/blink_platform.gypi

 {
   'includes': [
     'platform_generated.gypi',
   ],
   'variables': {
     'platform_files': [
       'AsyncFileSystemCallbacks.h',
       'CalculationValue.h',
       'CheckedInt.h',
       'ContentDecryptionModuleResult.h',
@@ skipping 1032 matching lines @@
       'v8_inspector/InjectedScriptHost.cpp',
       'v8_inspector/InjectedScriptHost.h',
       'v8_inspector/InspectedContext.cpp',
       'v8_inspector/InspectedContext.h',
       'v8_inspector/JavaScriptCallFrame.cpp',
       'v8_inspector/JavaScriptCallFrame.h',
       'v8_inspector/MuteConsoleScope.h',
       'v8_inspector/ScriptBreakpoint.h',
       'v8_inspector/RemoteObjectId.cpp',
       'v8_inspector/RemoteObjectId.h',
-      'v8_inspector/V8AsyncCallTracker.cpp',
-      'v8_inspector/V8AsyncCallTracker.h',
       'v8_inspector/V8DebuggerAgentImpl.cpp',
       'v8_inspector/V8DebuggerAgentImpl.h',
       'v8_inspector/V8DebuggerImpl.cpp',
       'v8_inspector/V8DebuggerImpl.h',
       'v8_inspector/V8DebuggerScript.cpp',
       'v8_inspector/V8DebuggerScript.h',
       'v8_inspector/V8FunctionCall.cpp',
       'v8_inspector/V8FunctionCall.h',
       'v8_inspector/V8HeapProfilerAgentImpl.cpp',
       'v8_inspector/V8HeapProfilerAgentImpl.h',
@@ skipping 233 matching lines @@
       ['OS!="mac"',
         {
           'platform_test_files': [
             'scroll/ScrollAnimatorTest.cpp',
           ],
         }
       ],
     ],
   },
 }