InstantExtended: Add js api for custom logo.

chrome/browser/ui/browser_instant_controller.cc

Index: chrome/browser/ui/browser_instant_controller.cc
diff --git a/chrome/browser/ui/browser_instant_controller.cc b/chrome/browser/ui/browser_instant_controller.cc
index 6b3504243c9413dc8c5752ca41165a1c5fbc746c..1c348da2c42979992be1a0aaac7f718aa20c4cbb 100644
--- a/chrome/browser/ui/browser_instant_controller.cc
+++ b/chrome/browser/ui/browser_instant_controller.cc
@@ -95,6 +95,10 @@ void BrowserInstantController::CommitInstant(TabContents* preview,
   }
 }
 
+void BrowserInstantController::SetHasCustomLogo(bool has_logo) {
+  browser_->window()->SetInstantHasCustomLogo(has_logo);

[samarth, 2012/10/10 22:16:53]

I agree with Sreeram that plumbing this through BrowserView feels weird.

Using a SearchMode state makes some sense since SearchViewController uses the
state to determine what kind of UI to show. So a NTP_NO_LOGO state might work. 
On the other hand that complicates the state transitions there a lot more. 

Yet another option is to create a new Observer interface for listening to state
changes in the Instant overlay. That seems a bit heavyweight for a single bool
but could make more sense if we need to pass through other state here.

+}
+
 void BrowserInstantController::SetSuggestedText(
     const string16& text,
     InstantCompleteBehavior behavior) {