Fix native key code under X11.

The WebKeyboardEvent.nativeKeyCode was incorrectly set
to the X keysym (interpretation of the key) rather than
the X keycode (physical key identifier), which broke
Chromoting.

BUG=412435

Review URL: https://codereview.chromium.org/626433003

Cr-Commit-Position: refs/heads/master@{#298080}
(cherry picked from commit e07fa56)

TBR=ben

Review URL: https://codereview.chromium.org/629843003

Cr-Commit-Position: refs/branch-heads/2171@{#51}
Cr-Branched-From: 267aeeb-refs/heads/master@{#297060}

content/browser/renderer_host/web_input_event_aura.cc

@@ -10,8 +10,8 @@
 #include "ui/events/event.h"
 #include "ui/events/event_utils.h"
 
-#if defined(USE_OZONE)
-#include "ui/events/keycodes/keyboard_code_conversion.h"
+#if defined(USE_X11) || defined(USE_OZONE)
+#include "ui/events/keycodes/dom4/keycode_converter.h"
 #endif
 
 namespace content {
@@ -50,7 +50,8 @@ blink::WebKeyboardEvent MakeWebKeyboardEventFromAuraEvent(
     webkit_event.isSystemKey = true;
 
   webkit_event.windowsKeyCode = event->GetLocatedWindowsKeyboardCode();
-  webkit_event.nativeKeyCode = event->platform_keycode();
+  webkit_event.nativeKeyCode =
+    ui::KeycodeConverter::CodeToNativeKeycode(event->code().c_str());
   webkit_event.unmodifiedText[0] = event->GetUnmodifiedText();
   webkit_event.text[0] = event->GetText();