added CTRL+Click and SHIFT+Click handler for context menu, Back and Forward.

content/browser/tab_contents/tab_contents_delegate.cc

Index: content/browser/tab_contents/tab_contents_delegate.cc
diff --git a/content/browser/tab_contents/tab_contents_delegate.cc b/content/browser/tab_contents/tab_contents_delegate.cc
index 96e99fc5a89c058dcded90ea23502bd43df8e4db..92b373ffa2dadf73676c8033299a3d41ce5fcec7 100644
--- a/content/browser/tab_contents/tab_contents_delegate.cc
+++ b/content/browser/tab_contents/tab_contents_delegate.cc
@@ -10,6 +10,12 @@
 #include "content/common/url_constants.h"
 #include "ui/gfx/rect.h"
 
+void TabContentsDelegate::GoBack(WindowOpenDisposition disposition) {
+}
+
+void TabContentsDelegate::GoForward(WindowOpenDisposition disposition) {
+}
+
 std::string TabContentsDelegate::GetNavigationHeaders(const GURL& url) {
   return std::string();
 }