Remove usages of WebContents::GetRenderViewHost().

This CL was uploaded by git cl split.

R=lazyboy@chromium.org

Bug: 1142671
Change-Id: I7c026fe91d2a8333295694d6b9bae1aaf62a0bd4
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2501124
Auto-Submit: Lucas Gadani <lfg@chromium.org>
Reviewed-by: Istiaque Ahmed <lazyboy@chromium.org>
Commit-Queue: Istiaque Ahmed <lazyboy@chromium.org>
Cr-Commit-Position: refs/heads/master@{#821129}

components/renderer_context_menu/render_view_context_menu_base.cc

@@ -295,7 +295,7 @@ void RenderViewContextMenuBase::RemoveAdjacentSeparators() {
 }
 
 RenderViewHost* RenderViewContextMenuBase::GetRenderViewHost() const {
-  return source_web_contents_->GetRenderViewHost();
+  return source_web_contents_->GetMainFrame()->GetRenderViewHost();
 }
 
 WebContents* RenderViewContextMenuBase::GetWebContents() const {