a11y: Update Shortcuts search box

Stop showing the back button in the search box to remove an unnecessary
tab stop.

Keep the placeholder text left justified and a consistent color with or
without focus.

Video: https://bugs.chromium.org/p/chromium/issues/detail?id=1005166#c27

Fixed: 1005166
Change-Id: Ie6daa2fd659122ca88bda39c2ab2dd36de2acf98
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2499803
Commit-Queue: Gavin Williams <gavinwill@chromium.org>
Reviewed-by: Xiyuan Xia <xiyuan@chromium.org>
Cr-Commit-Position: refs/heads/master@{#821315}

ash/search_box/search_box_constants.h

@@ -38,6 +38,10 @@ constexpr int kSearchBoxIconSize = 24;
 // The size of the image button in the search box.
 constexpr int kSearchBoxButtonSizeDip = 40;
 
+// Color of placeholder text in zero query state.
+constexpr SkColor kZeroQuerySearchboxColor =
+    SkColorSetARGB(0x8A, 0x00, 0x00, 0x00);
+
 }  // namespace ash
 
 #endif  // ASH_SEARCH_BOX_SEARCH_BOX_CONSTANTS_H_

ash/search_box/search_box_view_base.cc

@@ -47,10 +47,6 @@ constexpr SkColor kSelectedColor = SkColorSetARGB(15, 0, 0, 0);
 
 constexpr SkColor kSearchTextColor = SkColorSetRGB(0x33, 0x33, 0x33);
 
-// Color of placeholder text in zero query state.
-constexpr SkColor kZeroQuerySearchboxColor =
-    SkColorSetARGB(0x8A, 0x00, 0x00, 0x00);
-
 }  // namespace
 
 // A background that paints a solid white rounded rect with a thin grey

ash/shortcut_viewer/views/keyboard_shortcut_view.cc

@@ -336,7 +336,6 @@ void KeyboardShortcutView::BackButtonPressed() {
 void KeyboardShortcutView::ActiveChanged(ash::SearchBoxViewBase* sender) {
   const bool is_search_box_active = sender->is_search_box_active();
   is_search_box_empty_ = sender->IsSearchBoxTrimmedQueryEmpty();
-  sender->ShowBackOrGoogleIcon(is_search_box_active);
   if (is_search_box_active) {
     base::RecordAction(
         base::UserMetricsAction("KeyboardShortcutViewer.Search"));

ash/shortcut_viewer/views/keyboard_shortcut_view_unittest.cc

@@ -183,13 +183,14 @@ TEST_F(KeyboardShortcutViewTest, FocusOnSearchBox) {
 
   // Press a key should enter search mode.
   KeyPress(ui::VKEY_A, /*should_insert=*/true);
-  EXPECT_TRUE(GetSearchBoxView()->back_button()->GetVisible());
+  EXPECT_FALSE(GetSearchBoxView()->back_button()->GetVisible());
+  EXPECT_TRUE(GetSearchBoxView()->close_button()->GetVisible());
   EXPECT_FALSE(GetSearchBoxView()->search_box()->GetText().empty());
 
-  // Case 2: Exit search mode by clicking |back_button|. The focus should be on
+  // Case 2: Exit search mode by clicking |close_button|. The focus should be on
   // search box.
   GetSearchBoxView()->ButtonPressed(
-      GetSearchBoxView()->back_button(),
+      GetSearchBoxView()->close_button(),
       ui::MouseEvent(ui::ET_MOUSE_PRESSED, gfx::Point(), gfx::Point(),
                      base::TimeTicks(), ui::EF_LEFT_MOUSE_BUTTON,
                      ui::EF_LEFT_MOUSE_BUTTON));

ash/shortcut_viewer/views/ksv_search_box_view.cc

@@ -36,8 +36,7 @@ KSVSearchBoxView::KSVSearchBoxView(ash::SearchBoxViewDelegate* delegate)
   UpdateBackgroundColor(kDefaultSearchBoxBackgroundColor);
   search_box()->SetBackgroundColor(SK_ColorTRANSPARENT);
   search_box()->SetColor(gfx::kGoogleGrey900);
-  search_box()->set_placeholder_text_color(gfx::kGoogleGrey900);
-  search_box()->set_placeholder_text_draw_flags(gfx::Canvas::TEXT_ALIGN_CENTER);
+  SetPlaceholderTextAttributes();
   const base::string16 search_box_name(
       l10n_util::GetStringUTF16(IDS_KSV_SEARCH_BOX_ACCESSIBILITY_NAME));
   search_box()->SetPlaceholderText(search_box_name);
@@ -139,4 +138,17 @@ void KSVSearchBoxView::SetupBackButton() {
   back->SetVisible(false);
 }
 
+void KSVSearchBoxView::OnSearchBoxActiveChanged(bool active) {
+  // Update to override default placeholder attributes set by base class when
+  // the search box is no longer active.
+  SetPlaceholderTextAttributes();
+}
+
+void KSVSearchBoxView::SetPlaceholderTextAttributes() {
+  search_box()->set_placeholder_text_color(ash::kZeroQuerySearchboxColor);
+  search_box()->set_placeholder_text_draw_flags(
+      base::i18n::IsRTL() ? gfx::Canvas::TEXT_ALIGN_RIGHT
+                          : gfx::Canvas::TEXT_ALIGN_LEFT);
+}
+
 }  // namespace keyboard_shortcut_viewer

ash/shortcut_viewer/views/ksv_search_box_view.h

@@ -31,12 +31,16 @@ class KSVSearchBoxView : public ash::SearchBoxViewBase {
 
   void SetAccessibleValue(const base::string16& value);
 
+  // SearchBoxViewBase:
+  void OnSearchBoxActiveChanged(bool active) override;
+
  private:
   // SearchBoxViewBase:
   void UpdateBackgroundColor(SkColor color) override;
   void UpdateSearchBoxBorder() override;
   void SetupCloseButton() override;
   void SetupBackButton() override;
+  void SetPlaceholderTextAttributes();
 
   // Accessibility data value. Used to pronounce the number of search results.
   base::string16 accessible_value_;