Making answer card to behave like other results.

chrome/browser/ui/app_list/search_answer_web_contents_delegate.cc

 // Copyright 2017 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "chrome/browser/ui/app_list/search_answer_web_contents_delegate.h"
 
 #include "base/command_line.h"
 #include "base/metrics/histogram_macros.h"
 #include "base/metrics/user_metrics.h"
 #include "base/strings/utf_string_conversions.h"
 #include "chrome/browser/profiles/profile.h"
 #include "chrome/browser/ui/browser_navigator.h"
 #include "chrome/browser/ui/browser_navigator_params.h"
 #include "content/public/browser/navigation_handle.h"
 #include "content/public/browser/render_view_host.h"
+#include "content/public/browser/render_widget_host.h"
+#include "content/public/browser/render_widget_host_view.h"
 #include "content/public/browser/web_contents.h"
 #include "content/public/browser/web_contents_delegate.h"
 #include "content/public/common/renderer_preferences.h"
 #include "net/http/http_response_headers.h"
 #include "net/http/http_status_code.h"
 #include "ui/app_list/app_list_features.h"
 #include "ui/app_list/app_list_model.h"
 #include "ui/app_list/search_box_model.h"
 #include "ui/views/controls/webview/webview.h"
 #include "ui/views/widget/widget.h"
@@ skipping 126 matching lines @@
 
   content::NavigationController::LoadURLParams load_params(
       current_request_url_);
   load_params.transition_type = ui::PAGE_TRANSITION_AUTO_TOPLEVEL;
   load_params.should_clear_history_list = true;
   web_contents_->GetController().LoadURLWithParams(load_params);
   server_request_start_time_ = base::TimeTicks::Now();
 
   // We are going to call WebContents::GetPreferredSize().
   web_contents_->GetRenderViewHost()->EnablePreferredSizeMode();
+
+  // Make the webview transparent since it's going to be shown on top of a
+  // highlightable button.
+  content::RenderWidgetHostView* render_view_host_view =
+      web_contents_->GetRenderViewHost()->GetWidget()->GetView();
+  // The RenderWidgetHostView may be null if the renderer has crashed.
+  if (render_view_host_view)
+    render_view_host_view->SetBackgroundColor(SK_ColorTRANSPARENT);

[xiyuan, 2017/05/25 16:42:53]

There might be a few edge cases. We had WebContentsSetBackgroundColor [1] that
can be used for this. Can we move it to a common place and use it here as well ?

[1]:
https://cs.chromium.org/chromium/src/chrome/browser/chromeos/login/ui/web_con...

[vadimt, 2017/05/25 20:15:16]

Done.

 }
 
 void SearchAnswerWebContentsDelegate::UpdatePreferredSize(
     content::WebContents* web_contents,
     const gfx::Size& pref_size) {
   is_card_size_ok_ =
       IsCardSizeOk(pref_size) || features::IsAnswerCardDarkRunEnabled();
   model_->SetSearchAnswerAvailable(is_card_size_ok_ && received_answer_ &&
                                    !web_contents_->IsLoading());
-  if (!features::IsAnswerCardDarkRunEnabled())
-    web_view_->SetPreferredSize(pref_size);
+  web_view_->SetPreferredSize(pref_size);
   if (!answer_loaded_time_.is_null()) {
     UMA_HISTOGRAM_TIMES("SearchAnswer.ResizeAfterLoadTime",
                         base::TimeTicks::Now() - answer_loaded_time_);
   }
 }
 
 content::WebContents* SearchAnswerWebContentsDelegate::OpenURLFromTab(
     content::WebContents* source,
     const content::OpenURLParams& params) {
   if (!params.user_gesture)
@@ skipping 93 matching lines @@
     return;
 
   RecordRequestResult(
       is_card_size_ok_
           ? SearchAnswerRequestResult::REQUEST_RESULT_RECEIVED_ANSWER
           : SearchAnswerRequestResult::
                 REQUEST_RESULT_RECEIVED_ANSWER_TOO_LARGE);
 }
 
 }  // namespace app_list