Add a command line flag to disable infobars.

chrome/browser/tab_contents/tab_contents.cc

Index: chrome/browser/tab_contents/tab_contents.cc
===================================================================
--- chrome/browser/tab_contents/tab_contents.cc	(revision 42751)
+++ chrome/browser/tab_contents/tab_contents.cc	(working copy)
@@ -955,6 +955,11 @@
 }
 
 void TabContents::AddInfoBar(InfoBarDelegate* delegate) {
+  if (delegate_ && !delegate_->infobars_enabled()) {
+    delegate->InfoBarClosed();
+    return;
+  }
+
   // Look through the existing InfoBarDelegates we have for a match. If we've
   // already got one that matches, then we don't add the new one.
   for (int i = 0; i < infobar_delegate_count(); ++i) {
@@ -981,6 +986,10 @@
 }
 
 void TabContents::RemoveInfoBar(InfoBarDelegate* delegate) {
+  if (delegate_ && !delegate_->infobars_enabled()) {
+    return;
+  }
+
   std::vector<InfoBarDelegate*>::iterator it =
       find(infobar_delegates_.begin(), infobar_delegates_.end(), delegate);
   if (it != infobar_delegates_.end()) {
@@ -1001,6 +1010,11 @@
 
 void TabContents::ReplaceInfoBar(InfoBarDelegate* old_delegate,
                                  InfoBarDelegate* new_delegate) {
+  if (delegate_ && !delegate_->infobars_enabled()) {
+    new_delegate->InfoBarClosed();
+    return;
+  }
+
   std::vector<InfoBarDelegate*>::iterator it =
       find(infobar_delegates_.begin(), infobar_delegates_.end(), old_delegate);
   DCHECK(it != infobar_delegates_.end());