VR: Add omnibox hint text

This change puts a prompt string into the omnibox whenever the field is
empty.  Once a character is entered, or when the field later becomes
empty, the hint is shown.

BUG=
R=bshe
TBR=cpu@chromium.org

Cq-Include-Trybots: master.tryserver.chromium.android:android_optional_gpu_tests_rel;master.tryserver.chromium.linux:linux_optional_gpu_tests_rel;master.tryserver.chromium.mac:mac_optional_gpu_tests_rel;master.tryserver.chromium.win:win_optional_gpu_tests_rel
Change-Id: Ib05f091fb339a4c06d83a0502e1d0d1b51b0d277
Reviewed-on: https://chromium-review.googlesource.com/812208Reviewed-by: Biao She <bshe@chromium.org>
Commit-Queue: Christopher Grant <cjgrant@chromium.org>
Cr-Commit-Position: refs/heads/master@{#522317}

chrome/app/generated_resources.grd

@@ -5178,7 +5178,7 @@ Keep your key file in a safe place. You will need it to create new versions of y
       <message name="IDS_OMNIBOX_CLEAR_ALL" desc="Accessibility text for the button that deletes all text input from the omnibox on touch devices.">
         Clear input
       </message>
-      <if expr="is_android">
+      <if expr="is_android or enable_vr">
         <message name="IDS_SEARCH_OR_TYPE_URL" desc="Prompt to enter text into the text field that will either perform web searches or navigate to a URL. [CHAR-LIMIT=38]" formatter_data="android_java">
           Search or type URL
         </message>

chrome/browser/vr/elements/text_input.cc

@@ -112,6 +112,10 @@ void TextInput::SetCursorColor(SkColor color) {
   cursor_element_->SetColor(color);
 }
 
+void TextInput::SetHintColor(SkColor color) {
+  hint_element_->SetColor(color);
+}
+
 void TextInput::UpdateInput(const TextInputInfo& info) {
   if (text_info_ == info)
     return;

chrome/browser/vr/elements/text_input.h

@@ -43,6 +43,7 @@ class TextInput : public UiElement {
   void SetHintText(const base::string16& text);
   void SetTextColor(SkColor color);
   void SetCursorColor(SkColor color);
+  void SetHintColor(SkColor color);
   void SetTextInputDelegate(TextInputDelegate* text_input_delegate);
 
   bool OnBeginFrame(const base::TimeTicks& time,

chrome/browser/vr/model/color_scheme.cc

@@ -114,6 +114,7 @@ void InitializeColorSchemes() {
   normal_scheme.omnibox_background = 0xFFEEEEEE;
   normal_scheme.omnibox_icon = 0xA6000000;
   normal_scheme.omnibox_text = 0xFF595959;
+  normal_scheme.omnibox_hint = 0xFF999999;
   normal_scheme.omnibox_suggestion_content = 0xFF595959;
   normal_scheme.omnibox_suggestion_description = 0xFF5595FE;
   normal_scheme.cursor = 0xFF5595FE;

chrome/browser/vr/model/color_scheme.h

@@ -106,6 +106,7 @@ struct ColorScheme {
   SkColor omnibox_background;
   SkColor omnibox_icon;
   SkColor omnibox_text;
+  SkColor omnibox_hint;
   SkColor omnibox_suggestion_content;
   SkColor omnibox_suggestion_description;
 

chrome/browser/vr/ui_scene_creator.cc

@@ -1140,6 +1140,8 @@ void UiSceneCreator::CreateOmnibox() {
       VR_BIND(TextInputInfo, Model, model_, omnibox_text_field_info,
               UiBrowserInterface, browser_, StartAutocomplete(value.text)));
   omnibox_text_field->SetSize(width, 0);
+  omnibox_text_field->SetHintText(
+      l10n_util::GetStringUTF16(IDS_SEARCH_OR_TYPE_URL));
   omnibox_text_field->set_name(kOmniboxTextField);
   omnibox_text_field->set_x_anchoring(LEFT);
   omnibox_text_field->set_x_centering(LEFT);
@@ -1158,6 +1160,8 @@ void UiSceneCreator::CreateOmnibox() {
             &TextInput::SetTextColor);
   BindColor(model_, omnibox_text_field.get(), &ColorScheme::cursor,
             &TextInput::SetCursorColor);
+  BindColor(model_, omnibox_text_field.get(), &ColorScheme::omnibox_hint,
+            &TextInput::SetHintColor);
 
   scene_->AddUiElement(kOmniboxContainer, std::move(omnibox_text_field));