Remove logic to reset input method more than needed

content/browser/renderer_host/render_widget_host_view_aura.cc

 // Copyright (c) 2012 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "content/browser/renderer_host/render_widget_host_view_aura.h"
 
 #include <set>
 #include <utility>
 
 #include "base/auto_reset.h"
@@ skipping 2963 matching lines @@
   if (state && state->type != ui::TEXT_INPUT_TYPE_NONE) {
     // Start monitoring the composition information if the focused node is
     // editable.
     RenderWidgetHostImpl* last_active_widget =
         text_input_manager_->GetActiveWidget();
     last_active_widget_routing_id_ = last_active_widget->GetRoutingID();
     last_active_widget_process_id_ = last_active_widget->GetProcess()->GetID();
     last_active_widget->Send(new InputMsg_RequestCompositionUpdate(
         last_active_widget->GetRoutingID(), false /* immediate request */,
         true /* monitor request */));
+    if (has_composition_text_ && state->composition_start == -1) {

[aelias_OOO_until_Jul13, 2016/09/26 21:25:59]

Code in RenderWidgetHostViewAura only executes on Windows+Linux+ChromeOS, but
http://crbug.com/164427 is about Clank.

In general, I think code like this will be needed, before we add it, we should
have a test app that this fixes in order to sanity check that we're doing the
right thing (I assume you found google.com does not repro
http://crbug.com/164427 anymore nowadays even with the other deletions?)

If we cannot find a real-world example right now, we could try making an
artificial one, and/or land the Blink side of the change on dev channel and see
what breakage is reported to us.

[Changwan Ryu, 2016/09/27 03:00:12]

http://crbug.com/164427#c16
was the reason why it was originally implemented through cancelComposition(). I
can still reproduce the issue if I remove this logic.
You're right. It doesn't repro any more.
As for the other issue, I think a unit test should be enough.

[aelias_OOO_until_Jul13, 2016/09/27 04:39:47]

OK, understood, but the history (including the linked WebKit bug) shows this is
a totally artificial test case, and there's no evidence that any real-world
desktop JS forms rely on this.  In fact, the evidence cuts the other way because
the issue was preexisting before Aurimas noticed it while investigating an
Android issue.  Therefore I would prefer us not to go out of our way to add
extra lines of code to address this possible non-bug.  If there's a real issue
here, we'll hear about it in dev/beta channel and can always add these lines
then, with new confidence that they're useful.

+      // JS-triggered change caused composition to be lost.
+      // TODO(changwan): add a unit test.
+      GetInputMethod()->CancelComposition(this);
+      has_composition_text_ = false;
+    }
   } else {
     // Stop monitoring the composition information if the focused node is not
     // editable.
     RenderWidgetHostImpl* last_active_widget = RenderWidgetHostImpl::FromID(
         last_active_widget_process_id_, last_active_widget_routing_id_);
     if (last_active_widget) {
       last_active_widget->Send(new InputMsg_RequestCompositionUpdate(
           last_active_widget->GetRoutingID(), false /* immediate request */,
           false /* monitor request */));
     }
@@ skipping 46 matching lines @@
           ->GetTextSelection(focused_view)
           ->GetSelectedText(&selected_text)) {
     // Set the CLIPBOARD_TYPE_SELECTION to the ui::Clipboard.
     ui::ScopedClipboardWriter clipboard_writer(ui::CLIPBOARD_TYPE_SELECTION);
     clipboard_writer.WriteText(selected_text);
   }
 #endif  // defined(USE_X11) && !defined(OS_CHROMEOS)
 }
 
 }  // namespace content