DevTools: introduce --custom-devtools-frontend flag.

chrome/common/url_constants.cc

Index: chrome/common/url_constants.cc
diff --git a/chrome/common/url_constants.cc b/chrome/common/url_constants.cc
index 55572f34a0bac62a4a32709a900791177e12b500..5ce63ed65f51d434228f64b3c02f1ed0635764c3 100644
--- a/chrome/common/url_constants.cc
+++ b/chrome/common/url_constants.cc
@@ -38,6 +38,8 @@ const char kChromeUIConflictsURL[] = "chrome://conflicts/";
 const char kChromeUIConstrainedHTMLTestURL[] = "chrome://constrained-test/";
 const char kChromeUICrashesURL[] = "chrome://crashes/";
 const char kChromeUICreditsURL[] = "chrome://credits/";
+const char kChromeUIDevToolsCustomURL[] =
+    "chrome-devtools://devtools/custom/inspector.html";
 const char kChromeUIDevicesURL[] = "chrome://devices/";
 const char kChromeUIDevToolsURL[] =
     "chrome-devtools://devtools/bundled/inspector.html";
@@ -181,6 +183,7 @@ const char kChromeUIDevicesHost[] = "devices";
 const char kChromeUIDevToolsHost[] = "devtools";
 const char kChromeUIDevToolsBundledPath[] = "bundled";
 const char kChromeUIDevToolsRemotePath[] = "remote";
+const char kChromeUIDevToolsCustomPath[] = "custom";
 const char kChromeUIDNSHost[] = "dns";
 const char kChromeUIDomainReliabilityInternalsHost[] =
     "domain-reliability-internals";