Removed |which| from KeyboardEvent and MouseEvent.

third_party/WebKit/Source/core/events/UIEventInit.idl

Index: third_party/WebKit/Source/core/events/UIEventInit.idl
diff --git a/third_party/WebKit/Source/core/events/UIEventInit.idl b/third_party/WebKit/Source/core/events/UIEventInit.idl
index a994a6be9fdf72d6423fbb079c88cbcabf7cb14c..b0abe7d0083aca85d49fcbca9b7af8632d74051a 100644
--- a/third_party/WebKit/Source/core/events/UIEventInit.idl
+++ b/third_party/WebKit/Source/core/events/UIEventInit.idl
@@ -7,5 +7,6 @@
 dictionary UIEventInit : EventInit {
     Window? view = null;
     long detail = 0;
+    unsigned long which = 0;

[dtapuska, 2017/05/09 21:22:37]

Shouldn't the constructor of the UIEvent now store this field? And we should use
it instead of having virtuals for which?

[use mustaq_at_chromium.org, 2017/05/10 17:48:35]

The problem is that KeyboardEvent.which() ultimately depends on 3 fields
(windows_key_code, native_key_code and text[0]) of WebKeyboardEvent. Until the
stored WebKeyboardEvent is made read-only, I don't see an efficient way to store
the value in UIEvent.

[use mustaq_at_chromium.org, 2017/05/11 20:47:46]

As discussed offline, I will bring back the UIEventInit.which in a follow-up CL
.

     InputDeviceCapabilities? sourceCapabilities = null;
 };