Add a new field trial for Instant.

chrome/browser/instant/instant_controller.cc

Index: chrome/browser/instant/instant_controller.cc
diff --git a/chrome/browser/instant/instant_controller.cc b/chrome/browser/instant/instant_controller.cc
index ffbfc3e855cdebcca4f7ce391336118fa136bdee..d5d90c920930040d5b02cf54173a2921f71805c1 100644
--- a/chrome/browser/instant/instant_controller.cc
+++ b/chrome/browser/instant/instant_controller.cc
@@ -175,14 +175,19 @@ bool InstantController::Update(TabContentsWrapper* tab_contents,
   // trial to normal mode, with no intervening call to DestroyPreviewContents().
   // This would leave the loader in a weird state, which would manifest if the
   // user pressed <Enter> without calling Update(). TODO(sreeram): Handle it.
-  if (InstantFieldTrial::IsHiddenExperiment(tab_contents->profile())) {
-    // For the HIDDEN field trial we process |user_text| at commit time, which
+  if (InstantFieldTrial::IsSilentExperiment(tab_contents->profile())) {
+    // For the SILENT field trial we process |user_text| at commit time, which
     // means we're never really out of date.
     is_out_of_date_ = false;
     loader_->MaybeLoadInstantURL(tab_contents, template_url);
     return true;
   }
 
+  // For the HIDDEN field trial, never send back suggestions to the omnibox.

[sky, 2011/10/24 15:03:31]

This is a bit obscure. How about moving this after the call to UpdateLoader and
replace with suggested_text->clear()

[sreeram, 2011/10/24 17:14:50]

Done.

+  string16 ignore_suggested_text;
+  if (InstantFieldTrial::IsHiddenExperiment(tab_contents->profile()))
+    suggested_text = &ignore_suggested_text;
+
   UpdateLoader(template_url, match.destination_url, match.transition, user_text,
                verbatim, suggested_text);
 
@@ -236,9 +241,12 @@ bool InstantController::PrepareForCommit() {
   if (is_out_of_date_ || !loader_.get())
     return false;
 
-  // If we are not in the HIDDEN field trial, return the status of the preview.
-  if (!InstantFieldTrial::IsHiddenExperiment(tab_contents_->profile()))
+  // If we are not in the HIDDEN or SILENT field trials, return the status of
+  // the preview.
+  if (!InstantFieldTrial::IsHiddenExperiment(tab_contents_->profile()) &&
+      !InstantFieldTrial::IsSilentExperiment(tab_contents_->profile())) {
     return IsCurrent();
+  }
 
   TemplateURLService* model = TemplateURLServiceFactory::GetForProfile(
       tab_contents_->profile());
@@ -419,7 +427,10 @@ void InstantController::SetSuggestedTextFor(
     InstantLoader* loader,
     const string16& text,
     InstantCompleteBehavior behavior) {
-  delegate_->SetSuggestedText(text, behavior);
+  if (!is_out_of_date_ &&
+      !InstantFieldTrial::IsHiddenExperiment(tab_contents_->profile())) {
+    delegate_->SetSuggestedText(text, behavior);
+  }
 }
 
 gfx::Rect InstantController::GetInstantBounds() {
@@ -463,8 +474,11 @@ void InstantController::UpdateIsDisplayable() {
   bool displayable =
       (!is_out_of_date_ && loader_.get() && loader_->ready() &&
        loader_->http_status_ok());
-  if (displayable == is_displayable_)
+  if (displayable == is_displayable_ ||
+      (displayable &&
+       InstantFieldTrial::IsHiddenExperiment(tab_contents_->profile()))) {

[sky, 2011/10/24 15:03:31]

Make this part of setting displayable.

[sreeram, 2011/10/24 17:14:50]

Done.

     return;
+  }
 
   is_displayable_ = displayable;
   if (!is_displayable_) {