Remove the CHECK in RenderWidget::GetInputMethodController

content/renderer/render_widget.cc

Index: content/renderer/render_widget.cc
diff --git a/content/renderer/render_widget.cc b/content/renderer/render_widget.cc
index 2d27a73bd52c0b5f31f1ef5b3fdbee254a315783..1cf201845233b06f3c088ecb6dbb320a7c63d1a3 100644
--- a/content/renderer/render_widget.cc
+++ b/content/renderer/render_widget.cc
@@ -2305,9 +2305,15 @@ blink::WebWidget* RenderWidget::GetWebWidget() const {
 
 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();
 }