Omnibox: Create Field Trial to Always Display Hint Text

This likely won't affect metrics much, but someone asked me to do it
so I am.  It's easy.

BUG=350200

Review URL: https://codereview.chromium.org/245993002

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@282194 0039d316-1c4b-4281-b951-d872f2087c98

chrome/browser/omnibox/omnibox_field_trial.cc

@@ -430,6 +430,12 @@ bool OmniboxFieldTrial::AddUWYTMatchEvenIfPromotedURLs() {
       kAddUWYTMatchEvenIfPromotedURLsRule) == "true";
 }
 
+bool OmniboxFieldTrial::DisplayHintTextWhenPossible() {
+  return chrome_variations::GetVariationParamValue(
+      kBundledExperimentFieldTrialName,
+      kDisplayHintTextWhenPossibleRule) == "true";
+}
+
 const char OmniboxFieldTrial::kBundledExperimentFieldTrialName[] =
     "OmniboxBundledExperimentV1";
 const char OmniboxFieldTrial::kShortcutsScoringMaxRelevanceRule[] =
@@ -448,6 +454,8 @@ const char OmniboxFieldTrial::kDisableInliningRule[] = "DisableInlining";
 const char OmniboxFieldTrial::kAnswersInSuggestRule[] = "AnswersInSuggest";
 const char OmniboxFieldTrial::kAddUWYTMatchEvenIfPromotedURLsRule[] =
     "AddUWYTMatchEvenIfPromotedURLs";
+const char OmniboxFieldTrial::kDisplayHintTextWhenPossibleRule[] =
+    "DisplayHintTextWhenPossible";
 
 const char OmniboxFieldTrial::kHUPNewScoringEnabledParam[] =
     "HUPExperimentalScoringEnabled";

chrome/browser/omnibox/omnibox_field_trial.h

@@ -309,6 +309,15 @@ class OmniboxFieldTrial {
   // the experiment isn't active.
   static bool AddUWYTMatchEvenIfPromotedURLs();
 
+  // ---------------------------------------------------------
+  // For the DisplayHintTextWhenPossible experiment that's part of the
+  // bundled omnibox field trial.
+
+  // Returns true if the omnibox should display hint text (Search
+  // <search engine> or type URL) when possible (i.e., the omnibox
+  // is otherwise non-empty).
+  static bool DisplayHintTextWhenPossible();
+
   // ---------------------------------------------------------
   // Exposed publicly for the sake of unittests.
   static const char kBundledExperimentFieldTrialName[];
@@ -326,6 +335,7 @@ class OmniboxFieldTrial {
   static const char kDisableInliningRule[];
   static const char kAnswersInSuggestRule[];
   static const char kAddUWYTMatchEvenIfPromotedURLsRule[];
+  static const char kDisplayHintTextWhenPossibleRule[];
 
   // Parameter names used by the HUP new scoring experiments.
   static const char kHUPNewScoringEnabledParam[];

chrome/browser/ui/cocoa/omnibox/omnibox_view_mac.mm

@@ -14,6 +14,7 @@
 #include "chrome/browser/autocomplete/autocomplete_match.h"
 #include "chrome/browser/autocomplete/chrome_autocomplete_scheme_classifier.h"
 #include "chrome/browser/browser_process.h"
+#include "chrome/browser/omnibox/omnibox_field_trial.h"
 #include "chrome/browser/search/search.h"
 #include "chrome/browser/ui/cocoa/location_bar/autocomplete_text_field_cell.h"
 #import "chrome/browser/ui/cocoa/location_bar/autocomplete_text_field_editor.h"
@@ -234,7 +235,8 @@ void OmniboxViewMac::Update() {
 }
 
 void OmniboxViewMac::UpdatePlaceholderText() {
-  if (chrome::ShouldDisplayOriginChip()) {
+  if (chrome::ShouldDisplayOriginChip() ||
+      OmniboxFieldTrial::DisplayHintTextWhenPossible()) {
     NSDictionary* placeholder_attributes = @{
       NSFontAttributeName : GetFieldFont(gfx::Font::NORMAL),
       NSForegroundColorAttributeName : [NSColor disabledControlTextColor]

chrome/browser/ui/views/omnibox/omnibox_view_views.cc

@@ -15,6 +15,7 @@
 #include "chrome/browser/autocomplete/autocomplete_match.h"
 #include "chrome/browser/autocomplete/chrome_autocomplete_scheme_classifier.h"
 #include "chrome/browser/command_updater.h"
+#include "chrome/browser/omnibox/omnibox_field_trial.h"
 #include "chrome/browser/search/search.h"
 #include "chrome/browser/ui/omnibox/omnibox_edit_controller.h"
 #include "chrome/browser/ui/omnibox/omnibox_edit_model.h"
@@ -256,7 +257,8 @@ void OmniboxViewViews::Update() {
 }
 
 void OmniboxViewViews::UpdatePlaceholderText() {
-  if (chrome::ShouldDisplayOriginChip())
+  if (chrome::ShouldDisplayOriginChip() ||
+      OmniboxFieldTrial::DisplayHintTextWhenPossible())
     set_placeholder_text(GetHintText());
 }