Adds selection expansion support for Contextual Search.

content/public/browser/web_contents.h

Index: content/public/browser/web_contents.h
diff --git a/content/public/browser/web_contents.h b/content/public/browser/web_contents.h
index ab0fe6df66aa4ccdd768fadbc80f9ab85b6bcb0a..cddfbe2367f89abe2a2ebb78c14430ba9ff56048 100644
--- a/content/public/browser/web_contents.h
+++ b/content/public/browser/web_contents.h
@@ -417,6 +417,10 @@ class WebContents : public PageNavigator,
   virtual void SelectAll() = 0;
   virtual void Unselect() = 0;
 
+  // Expand the selection in the focused frame by the given amounts.
+  virtual void ExpandSelectionByCharacterOffset(int start_adjust,
+                                                int end_adjust) = 0;
+
   // Replaces the currently selected word or a word around the cursor.
   virtual void Replace(const base::string16& word) = 0;