Adds Mojo IDL.

third_party/WebKit/Source/core/core_idl_files.gni

Index: third_party/WebKit/Source/core/core_idl_files.gni
diff --git a/third_party/WebKit/Source/core/core_idl_files.gni b/third_party/WebKit/Source/core/core_idl_files.gni
index 0a8ab8eec965178cbd48aa51039569c49c61b4e7..d94bf13b5171f0c4d99c28d89cc2e8c391b2ab0d 100644
--- a/third_party/WebKit/Source/core/core_idl_files.gni
+++ b/third_party/WebKit/Source/core/core_idl_files.gni
@@ -284,6 +284,9 @@ core_idl_files = get_path_info([
                                  "input/InputDeviceCapabilities.idl",
                                  "inspector/InspectorOverlayHost.idl",
                                  "loader/appcache/ApplicationCache.idl",
+                                 "mojo/Mojo.idl",
+                                 "mojo/MojoHandle.idl",
+                                 "mojo/MojoWatcher.idl",
                                  "observer/ResizeObserver.idl",
                                  "observer/ResizeObserverCallback.idl",
                                  "observer/ResizeObserverEntry.idl",
@@ -557,6 +560,11 @@ core_dictionary_idl_files =
                     "html/track/TrackEventInit.idl",
                     "imagebitmap/ImageBitmapOptions.idl",
                     "input/InputDeviceCapabilitiesInit.idl",
+                    "mojo/MojoCreateMessagePipeOptions.idl",
+                    "mojo/MojoCreateMessagePipeResult.idl",
+                    "mojo/MojoReadMessageOptions.idl",
+                    "mojo/MojoReadMessageResult.idl",
+                    "mojo/MojoWriteMessageOptions.idl",
                     "offscreencanvas/ImageEncodeOptions.idl",
                     "page/scrolling/ScrollStateInit.idl",
                     "timing/PerformanceObserverInit.idl",