Added back button when in folder view.

ui/app_list/views/search_box_view.cc

 // Copyright (c) 2012 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 "ui/app_list/views/search_box_view.h"
 
 #include <algorithm>
 
 #include "base/macros.h"
 #include "base/memory/ptr_util.h"
@@ skipping 164 matching lines @@
   if (is_fullscreen_app_list_enabled_) {
     google_icon_ = new views::ImageView();
     google_icon_->SetImage(gfx::CreateVectorIcon(
         kIcGoogleBlackIcon, kGoogleIconSize, kDefaultSearchboxColor));
     content_container_->AddChildView(google_icon_);
 
     search_box_->set_placeholder_text_color(kDefaultSearchboxColor);
     search_box_->set_placeholder_text_draw_flags(
         gfx::Canvas::TEXT_ALIGN_CENTER);
     search_box_->SetFontList(search_box_->GetFontList().DeriveWithSizeDelta(2));
+  }
+  back_button_ = new SearchBoxImageButton(this);
+  ui::ResourceBundle& rb = ui::ResourceBundle::GetSharedInstance();
+  back_button_->SetImage(views::ImageButton::STATE_NORMAL,
+                         rb.GetImageSkiaNamed(IDR_APP_LIST_FOLDER_BACK_NORMAL));
+  back_button_->SetImageAlignment(views::ImageButton::ALIGN_CENTER,
+                                  views::ImageButton::ALIGN_MIDDLE);
+  SetBackButtonLabel(false);
+
+  if (is_fullscreen_app_list_enabled_) {
+    content_container_->AddChildView(google_icon_);
   } else {
-    back_button_ = new SearchBoxImageButton(this);
-    ui::ResourceBundle& rb = ui::ResourceBundle::GetSharedInstance();
-    back_button_->SetImage(
-        views::ImageButton::STATE_NORMAL,
-        rb.GetImageSkiaNamed(IDR_APP_LIST_FOLDER_BACK_NORMAL));
-    back_button_->SetImageAlignment(views::ImageButton::ALIGN_CENTER,
-                                    views::ImageButton::ALIGN_MIDDLE);
-    SetBackButtonLabel(false);
     content_container_->AddChildView(back_button_);
-
     search_box_->set_placeholder_text_color(kHintTextColor);
   }
   content_container_->AddChildView(search_box_);
   layout->SetFlexForView(search_box_, 1);
 
   view_delegate_->GetSpeechUI()->AddObserver(this);
   ModelChanged();
 }
 
 SearchBoxView::~SearchBoxView() {
@@ skipping 119 matching lines @@
   if (!back_button_)
     return;
 
   base::string16 back_button_label(l10n_util::GetStringUTF16(
       folder ? IDS_APP_LIST_FOLDER_CLOSE_FOLDER_ACCESSIBILE_NAME
              : IDS_APP_LIST_BACK));
   back_button_->SetAccessibleName(back_button_label);
   back_button_->SetTooltipText(back_button_label);
 }
 
+void SearchBoxView::SwapGoogleIconWithBackButton(bool show_back_button) {

[vadimt, 2017/06/22 00:36:12]

"ShowBackOrGoogleIcon"

BTW, do we show Google icon if search provider is NOT Google?

[newcomer, 2017/06/22 16:49:07]

Done, and I opened a dialogue with our pm/ux crew.

+  if (!is_fullscreen_app_list_enabled_)
+    return;
+
+  if (show_back_button) {
+    content_container_->AddChildViewAt(
+        back_button_, content_container_->GetIndexOf(google_icon_));
+    content_container_->RemoveChildView(google_icon_);
+  } else {
+    content_container_->AddChildViewAt(
+        google_icon_, content_container_->GetIndexOf(back_button_));
+    content_container_->RemoveChildView(back_button_);
+  }
+  content_container_->Layout();
+}
+
 bool SearchBoxView::OnMouseWheel(const ui::MouseWheelEvent& event) {
   if (contents_view_)
     return contents_view_->OnMouseWheel(event);
 
   return false;
 }
 
 void SearchBoxView::OnEnabledChanged() {
   search_box_->SetEnabled(enabled());
   if (speech_button_)
@@ skipping 144 matching lines @@
   NotifyQueryChanged();
 }
 
 void SearchBoxView::OnSpeechRecognitionStateChanged(
     SpeechRecognitionState new_state) {
   SpeechRecognitionButtonPropChanged();
   SchedulePaint();
 }
 
 }  // namespace app_list