Interstitial call ShowContextMenu on Android

Override |ShowContextMenu()| in InterstitialPageImpl and have it call
|WebContentsViewAndroid.ShowContextMenu()| on Android. This is done to
show the floating text selection menu (see linked bug).

Bug: 823173
Change-Id: I01090aee43536cd06c8f8bc28ebccf5c2767d0d8
Reviewed-on: https://chromium-review.googlesource.com/977240Reviewed-by: Bo <boliu@chromium.org>
Reviewed-by: Carlos IL <carlosil@chromium.org>
Commit-Queue: Pedro Amaral <amaralp@chromium.org>
Cr-Commit-Position: refs/heads/master@{#546210}

content/browser/frame_host/interstitial_page_impl.cc

@@ -58,6 +58,10 @@
 #include "net/url_request/url_request_context_getter.h"
 #include "ui/base/page_transition_types.h"
 
+#if defined(OS_ANDROID)
+#include "content/browser/web_contents/web_contents_view_android.h"
+#endif
+
 using blink::WebDragOperation;
 using blink::WebDragOperationsMask;
 
@@ -794,6 +798,15 @@ void InterstitialPageImpl::CreateNewFullscreenWidget(int32_t render_process_id,
       << "InterstitialPage does not support showing full screen popups.";
 }
 
+void InterstitialPageImpl::ShowContextMenu(RenderFrameHost* render_frame_host,
+                                           const ContextMenuParams& params) {
+#if defined(OS_ANDROID)
+  static_cast<WebContentsViewAndroid*>(
+      static_cast<WebContentsImpl*>(web_contents())->GetView())
+      ->ShowContextMenu(render_frame_host, params);
+#endif
+}
+
 void InterstitialPageImpl::ShowCreatedWindow(int process_id,
                                              int main_frame_widget_route_id,
                                              WindowOpenDisposition disposition,

content/browser/frame_host/interstitial_page_impl.h

@@ -107,6 +107,8 @@ class CONTENT_EXPORT InterstitialPageImpl : public InterstitialPage,
                const NotificationDetails& details) override;
 
   // RenderFrameHostDelegate implementation:
+  void ShowContextMenu(RenderFrameHost* render_frame_host,
+                       const ContextMenuParams& params) override;
   bool OnMessageReceived(RenderFrameHostImpl* render_frame_host,
                          const IPC::Message& message) override;
   void RenderFrameCreated(RenderFrameHost* render_frame_host) override;