[inspector] Build inspector under v8_enable_inspector build flag.

src/inspector/inspector_protocol_config.json

 {
     "protocol": {
         "path": "js_protocol.json",
         "package": "src/inspector/protocol",
-        "output": "v8_inspector/protocol",
+        "output": "protocol",
         "namespace": ["v8_inspector", "protocol"]
     },
 
     "exported": {
-        "package": "src/inspector/public/protocol",
-        "output": "v8_inspector/public/protocol",
-        "string_header": "src/inspector/public/StringBuffer.h",
+        "package": "include/inspector",
+        "output": "../../include/inspector",
+        "string_header": "v8-inspector.h",
         "string_in": "StringView",
         "string_out": "std::unique_ptr<StringBuffer>",
-        "to_string_out": "StringBufferImpl::adopt(%s)"
+        "to_string_out": "StringBufferImpl::adopt(%s)",
+        "export_macro": "V8_EXPORT"
     },
 
     "lib": {
         "package": "src/inspector/protocol",
-        "output": "v8_inspector/protocol",
+        "output": "protocol",
         "string_header": "src/inspector/StringUtil.h",
         "platform_header": "src/inspector/ProtocolPlatform.h"
-    },
-
-    "class_export": {
-        "macro": "PLATFORM_EXPORT",
-        "header": "platform/PlatformExport.h"
     }
 }