Request Composition Range Updates for Focused GuestViews based on BrowserPlugins

content/browser/browser_plugin/browser_plugin_guest.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/browser_plugin/browser_plugin_guest.h"
 
 #include <stddef.h>
 
 #include <algorithm>
 
@@ skipping 632 matching lines @@
     // embedder shutdown or when the embedder navigates to a different page.
     // The call stack is roughly:
     // BrowserPluginGuest::SetFocus()
     // content::InterstitialPageImpl::Hide()
     // content::InterstitialPageImpl::DontProceed().
     //
     // TODO(lazyboy): Write a WebUI test once http://crbug.com/463674 is fixed.
     return;
   }
 
-  if (last_text_input_state_.get())
+  if (last_text_input_state_.get()) {
     guest_rwhv->TextInputStateChanged(*last_text_input_state_);
+    if (auto* rwh =
+            RenderWidgetHostImpl::From(guest_rwhv->GetRenderWidgetHost())) {
+      // We need composition range information for some IMEs. To get the
+      // updates, we need to explicitly ask the renderer to monitor and send the
+      // composition information changes. RenderWidgetHostView of the page will
+      // send the request to its process but the machinery for forwarding it to
+      // BrowserPlugin is not there. Therefore, we send a direct request to the
+      // guest process to start monitoring the state (see
+      // https://crbug.com/714771).
+      rwh->RequestCompositionUpdates(
+          false, last_text_input_state_->type != ui::TEXT_INPUT_TYPE_NONE);
+    }
+  }
 }
 
 void BrowserPluginGuest::DidFinishNavigation(
     NavigationHandle* navigation_handle) {
   if (navigation_handle->HasCommitted())
     RecordAction(base::UserMetricsAction("BrowserPlugin.Guest.DidNavigate"));
 }
 
 void BrowserPluginGuest::RenderViewReady() {
   if (GuestMode::IsCrossProcessFrameGuest(GetWebContents()))
@@ skipping 407 matching lines @@
           range, character_bounds);
 }
 #endif
 
 void BrowserPluginGuest::SetContextMenuPosition(const gfx::Point& position) {
   if (delegate_)
     delegate_->SetContextMenuPosition(position);
 }
 
 }  // namespace content