[DevTools] Split a part of V8Inspector into V8Debugger.

third_party/WebKit/Source/platform/blink_platform.gypi

 {
   'includes': [
     'platform_generated.gypi',
   ],
   'variables': {
     'platform_files': [
       'AsyncFileSystemCallbacks.h',
       'CalculationValue.h',
       'CheckedInt.h',
       'ContentDecryptionModuleResult.h',
@@ skipping 1066 matching lines @@
       'v8_inspector/JavaScriptCallFrame.cpp',
       'v8_inspector/JavaScriptCallFrame.h',
       'v8_inspector/ScriptBreakpoint.h',
       'v8_inspector/RemoteObjectId.cpp',
       'v8_inspector/RemoteObjectId.h',
       'v8_inspector/V8Compat.h',
       'v8_inspector/V8ConsoleAgentImpl.cpp',
       'v8_inspector/V8ConsoleAgentImpl.h',
       'v8_inspector/V8ConsoleMessage.cpp',
       'v8_inspector/V8ConsoleMessage.h',
+      'v8_inspector/V8Debugger.cpp',
+      'v8_inspector/V8Debugger.h',
       'v8_inspector/V8DebuggerAgentImpl.cpp',
       'v8_inspector/V8DebuggerAgentImpl.h',
       'v8_inspector/V8InspectorImpl.cpp',
       'v8_inspector/V8InspectorImpl.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 254 matching lines @@
       ['use_default_render_theme==1',
         {
           'platform_test_files': [
             'scroll/ScrollbarThemeAuraTest.cpp',
           ],
         }
       ],
     ],
   },
 }