Use static_cast instead of reinterpret_cast for downcasting

static_cast is better suited for downcasting since it can check that the
types are related.

/content/browser/web_contents/web_contents_view_mac.mm
This CL was uploaded by git cl split.

R=ellyjones@chromium.org

Change-Id: I23958320fc719b9b5f8179110aa789441313f251
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2435312
Auto-Submit: Kevin McNee <mcnee@chromium.org>
Reviewed-by: Elly Fong-Jones <ellyjones@chromium.org>
Commit-Queue: Elly Fong-Jones <ellyjones@chromium.org>
Cr-Commit-Position: refs/heads/master@{#811340}

content/browser/web_contents/web_contents_view_mac.mm

@@ -428,7 +428,7 @@ std::list<RenderWidgetHostViewMac*> WebContentsViewMac::GetChildViews() {
   std::list<RenderWidgetHostViewMac*> result;
   for (auto iter = child_views_.begin(); iter != child_views_.end();) {
     if (*iter) {
-      result.push_back(reinterpret_cast<RenderWidgetHostViewMac*>(iter->get()));
+      result.push_back(static_cast<RenderWidgetHostViewMac*>(iter->get()));
       iter++;
     } else {
       iter = child_views_.erase(iter);