Introduce ThreadedInputConnection behind a switch

content/renderer/input/render_widget_input_handler.cc

Index: content/renderer/input/render_widget_input_handler.cc
diff --git a/content/renderer/input/render_widget_input_handler.cc b/content/renderer/input/render_widget_input_handler.cc
index d5d5255c02f9c864a383a94ca1745f640d47461b..872a4e9b50365a72bf9ce0a4ac3779ea59c9ebba 100644
--- a/content/renderer/input/render_widget_input_handler.cc
+++ b/content/renderer/input/render_widget_input_handler.cc
@@ -9,6 +9,7 @@
 #include <utility>
 
 #include "base/auto_reset.h"
+#include "base/command_line.h"
 #include "base/metrics/histogram_macros.h"
 #include "base/trace_event/trace_event_synthetic_delay.h"
 #include "build/build_config.h"
@@ -17,6 +18,7 @@
 #include "content/common/input/input_event_ack.h"
 #include "content/common/input/input_event_ack_state.h"
 #include "content/common/input/web_input_event_traits.h"
+#include "content/public/common/content_switches.h"
 #include "content/renderer/gpu/render_widget_compositor.h"
 #include "content/renderer/ime_event_guard.h"
 #include "content/renderer/input/render_widget_input_handler_delegate.h"
@@ -208,12 +210,18 @@ void RenderWidgetInputHandler::HandleInputEvent(
 
 #if defined(OS_ANDROID)
   bool from_ime = false;
+  bool use_ime_thread = base::CommandLine::ForCurrentProcess()->HasSwitch(
+      switches::kUseImeThread);
 
   // For most keyboard events, we want the change source to be FROM_IME because
   // we don't need to update IME states in AdapterInputConnection.
   if (WebInputEvent::isKeyboardEventType(input_event.type)) {
     const WebKeyboardEvent& key_event =
         *static_cast<const WebKeyboardEvent*>(&input_event);
+    if (use_ime_thread) {
+      // We do not send state update for synthetic keys that accompany
+      // setComposingText / commitText.
+      from_ime = key_event.nativeKeyCode != 229;

[aelias_OOO_until_Jul13, 2016/01/21 07:43:05]

But this line implies you're still setting FROM_IME for character key events
coming from an attached physical keyboard?  That would cause your BlockingQueue
to get out of sync, no?  Anyway, see my proposal in render_widget.cc for a way
to avoid this whole problem space.

[Changwan Ryu, 2016/01/22 10:22:17]

Done. Thanks for finding it! Fixed as suggested!

     // TODO(changwan): this if-condition is a stop-gap solution to update IME
     // states in AdapterInputConnection when using DPAD navigation. This is not
     // a correct solution because InputConnection#getTextBeforeCursor()
@@ -221,13 +229,14 @@ void RenderWidgetInputHandler::HandleInputEvent(
     // correct value. The correct solution is either redesign the architecture
     // or emulate the DPAD behavior in AdapterInputConnection, either is
     // non-trivial.
-    if (key_event.nativeKeyCode != AKEYCODE_TAB &&
+    } else if (key_event.nativeKeyCode != AKEYCODE_TAB &&
         key_event.nativeKeyCode != AKEYCODE_DPAD_CENTER &&
         key_event.nativeKeyCode != AKEYCODE_DPAD_LEFT &&
         key_event.nativeKeyCode != AKEYCODE_DPAD_RIGHT &&
         key_event.nativeKeyCode != AKEYCODE_DPAD_UP &&
-        key_event.nativeKeyCode != AKEYCODE_DPAD_DOWN)
+        key_event.nativeKeyCode != AKEYCODE_DPAD_DOWN) {
       from_ime = true;
+    }
   }
 
   ImeEventGuard guard(widget_, false, from_ime);