Never showing context menu from the answer card.

Per UX.

Bug=712331

Review-Url: https://codereview.chromium.org/2847583003
Cr-Commit-Position: refs/heads/master@{#467759}

chrome/browser/ui/app_list/search_answer_web_contents_delegate.cc

@@ -112,6 +112,12 @@ content::WebContents* SearchAnswerWebContentsDelegate::OpenURLFromTab(
   return new_tab_params.target_contents;
 }
 
+bool SearchAnswerWebContentsDelegate::HandleContextMenu(
+    const content::ContextMenuParams& params) {
+  // Disable showing the menu.
+  return true;
+}
+
 void SearchAnswerWebContentsDelegate::DidFinishNavigation(
     content::NavigationHandle* navigation_handle) {
   if (navigation_handle->GetURL() != current_request_url_)

chrome/browser/ui/app_list/search_answer_web_contents_delegate.h

@@ -46,10 +46,13 @@ class SearchAnswerWebContentsDelegate : public content::WebContentsDelegate,
   // content::WebContentsDelegate overrides:
   void UpdatePreferredSize(content::WebContents* web_contents,
                            const gfx::Size& pref_size) override;
+
   content::WebContents* OpenURLFromTab(
       content::WebContents* source,
       const content::OpenURLParams& params) override;
 
+  bool HandleContextMenu(const content::ContextMenuParams& params) override;
+
   // content::WebContentsObserver overrides:
   void DidFinishNavigation(
       content::NavigationHandle* navigation_handle) override;