Add a feature flag, ArcPreImeKeyEventSupport.

For the details, please look at go/arc-key-event-dispatch.

Bug: b:148193316
Change-Id: If055711408545b746db04bd30079dbcbe1e95c98
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2206856Reviewed-by: Tetsui Ohkubo <tetsui@chromium.org>
Commit-Queue: Yuichiro Hanada <yhanada@chromium.org>
Cr-Commit-Position: refs/heads/master@{#770072}

chromeos/constants/chromeos_features.cc

@@ -34,6 +34,10 @@ const base::Feature kArcAdbSideloadingFeature{
 const base::Feature kArcManagedAdbSideloadingSupport{
     "ArcManagedAdbSideloadingSupport", base::FEATURE_DISABLED_BY_DEFAULT};
 
+// Controls whether to enable support for View.onKeyPreIme() of ARC apps.
+const base::Feature kArcPreImeKeyEventSupport{
+    "ArcPreImeKeyEventSupport", base::FEATURE_DISABLED_BY_DEFAULT};
+
 // Enables or disables auto screen-brightness adjustment when ambient light
 // changes.
 const base::Feature kAutoScreenBrightness{"AutoScreenBrightness",

chromeos/constants/chromeos_features.h

@@ -24,6 +24,8 @@ extern const base::Feature kArcAdbSideloadingFeature;
 COMPONENT_EXPORT(CHROMEOS_CONSTANTS)
 extern const base::Feature kArcManagedAdbSideloadingSupport;
 COMPONENT_EXPORT(CHROMEOS_CONSTANTS)
+extern const base::Feature kArcPreImeKeyEventSupport;
+COMPONENT_EXPORT(CHROMEOS_CONSTANTS)
 extern const base::Feature kAutoScreenBrightness;
 COMPONENT_EXPORT(CHROMEOS_CONSTANTS)
 extern const base::Feature kAssistAutoCorrect;