Add support for providers called when the omnibox is focused.

components/omnibox/autocomplete_provider.h

Index: components/omnibox/autocomplete_provider.h
diff --git a/components/omnibox/autocomplete_provider.h b/components/omnibox/autocomplete_provider.h
index 9c784ba563924f0ec8613fcab84352b7e21f2c1f..96102928a62bb1f3153d3a541f0d7916e0296a2d 100644
--- a/components/omnibox/autocomplete_provider.h
+++ b/components/omnibox/autocomplete_provider.h
@@ -197,6 +197,10 @@ class AutocompleteProvider
   // Returns this provider's type.
   Type type() const { return type_; }
 
+  // Returns whether the provider wants to provide matches in response to the
+  // omnibox being focused.
+  virtual bool ProvidesMatchesOnOmniboxFocus() const;
+
   // Returns a string describing this provider's type.
   const char* GetName() const;