Separate SwipeRefreshHandler and ContentViewCore

content/browser/web_contents/web_contents_android.cc

Index: content/browser/web_contents/web_contents_android.cc
diff --git a/content/browser/web_contents/web_contents_android.cc b/content/browser/web_contents/web_contents_android.cc
index 9be39aeb0fdd6b73a22c14f772554df23fcdc7cb..841d439b0ade07744780bda2d3341c21c12eb27f 100644
--- a/content/browser/web_contents/web_contents_android.cc
+++ b/content/browser/web_contents/web_contents_android.cc
@@ -23,6 +23,7 @@
 #include "content/browser/media/android/media_web_contents_observer_android.h"
 #include "content/browser/renderer_host/render_view_host_impl.h"
 #include "content/browser/web_contents/web_contents_impl.h"
+#include "content/browser/web_contents/web_contents_view_android.h"
 #include "content/common/devtools_messages.h"
 #include "content/common/frame_messages.h"
 #include "content/common/input_messages.h"
@@ -616,6 +617,17 @@ ScopedJavaLocalRef<jstring> WebContentsAndroid::GetEncoding(
                                                 web_contents_->GetEncoding());
 }
 
+void WebContentsAndroid::SetOverscrollRefreshHandler(
+    JNIEnv* env,
+    const base::android::JavaParamRef<jobject>& obj,
+    jlong overscroll_refresh_handler_ptr) {
+  WebContentsViewAndroid* view =
+      static_cast<WebContentsViewAndroid*>(web_contents_->GetView());
+  view->SetOverscrollRefreshHandler(
+      reinterpret_cast<ui::OverscrollRefreshHandler*>(

[Ted C, 2016/11/29 00:06:08]

I believe this is undefined behavior in C++ and somewhat dangerous.

This "kind" of discusses it:
http://stackoverflow.com/questions/7409565/how-to-use-reinterpret-cast-to-cas...

In general, you want dynamic cast, which we don't have in Chrome.  You also
don't know the pointer type, so you can't really use static casts either.

[rlanday, 2016/11/29 00:46:25]

Ah, interesting...

Fixing this (maybe by adding @CalledByNative and eliminating
swipe_refresh_handler.cc/.h as you're suggesting) seems like a fairly
substantial refactor, I will do this and then re-evaluate the other feedback

+          overscroll_refresh_handler_ptr));
+}
+
 void WebContentsAndroid::GetContentBitmap(
     JNIEnv* env,
     const JavaParamRef<jobject>& obj,