Remove the CHECK in RenderWidget::GetInputMethodController

content/renderer/render_widget.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/renderer/render_widget.h"
 
 #include <memory>
 #include <utility>
 
 #include "base/auto_reset.h"
@@ skipping 2287 matching lines @@
                                      image.getSkBitmap(), imageOffset,
                                      possible_drag_event_info_));
 }
 
 blink::WebWidget* RenderWidget::GetWebWidget() const {
   return webwidget_internal_;
 }
 
 blink::WebInputMethodController* RenderWidget::GetInputMethodController()
     const {
-  // TODO(ekaramad): Remove this CHECK when GetWebWidget() is
-  // always a WebFrameWidget.
-  CHECK(GetWebWidget()->isWebFrameWidget());
+  // TODO(ekaramad): Remove this condition when GetWebWidget() is always a
+  // WebFrameWidget, or find a better way to obtain the WebFrameWidget for
+  // this RenderWidget.
+  if (!GetWebWidget()->isWebFrameWidget()) {
+    // It is possible to get here if this is a top-level RenderWidget and an IME
+    // IPC is received during page navigation, in which case GetWebWidget()
+    // yields a WebViewImpl instead of a WebFrameWiget.
+    return nullptr;

[EhsanK, 2016/11/24 01:21:39]

I should also note that this method can return null pointer for other reasons so
as far as returning nullptr goes, it is OK.

getActiveWebInputMethodController() can legitimately return nullptr, e.g., if
the focused frame on the page belongs to different local root.

+  }
   return static_cast<blink::WebFrameWidget*>(GetWebWidget())
       ->getActiveWebInputMethodController();
 }
 
 }  // namespace content