Fix crash/leak issue in native_view_host_gtk.cc.

views/controls/native/native_view_host_wrapper.h

Index: views/controls/native/native_view_host_wrapper.h
diff --git a/views/controls/native/native_view_host_wrapper.h b/views/controls/native/native_view_host_wrapper.h
index 948f0ce6c5eec9a6301f29e0a43dc255ca8c9593..056584ea55a1854611653fd5734c4c0c45d48499 100644
--- a/views/controls/native/native_view_host_wrapper.h
+++ b/views/controls/native/native_view_host_wrapper.h
@@ -23,8 +23,9 @@ class NativeViewHostWrapper {
 
   // Called before the attached gfx::NativeView is detached from the
   // NativeViewHost, allowing the wrapper to perform platform-specific
-  // cleanup.
-  virtual void NativeViewDetaching() = 0;
+  // cleanup. |destroyed| is true if the native view is detached
+  // because it's being destroyed, or false otherwise.
+  virtual void NativeViewDetaching(bool destroyed) = 0;
 
   // Called when our associated NativeViewHost is added to a View hierarchy
   // rooted at a valid Widget.