Fix crashes in DownloadRequestLimiter when extension popups/bubbles initiate downloads automatically

chrome/browser/ui/tab_contents/tab_contents_wrapper.h

Index: chrome/browser/ui/tab_contents/tab_contents_wrapper.h
diff --git a/chrome/browser/ui/tab_contents/tab_contents_wrapper.h b/chrome/browser/ui/tab_contents/tab_contents_wrapper.h
index 3fc5e14ef66cd57737255cc285abaf671cf706b4..00ef34bd71a0d3bc64b0ee73c8af887b3a4df379 100644
--- a/chrome/browser/ui/tab_contents/tab_contents_wrapper.h
+++ b/chrome/browser/ui/tab_contents/tab_contents_wrapper.h
@@ -22,7 +22,6 @@ class BlockedContentTabHelper;
 class BookmarkTabHelper;
 class ConstrainedWindowTabHelper;
 class CoreTabHelper;
-class DownloadRequestLimiterObserver;
 class ExtensionTabHelper;
 class ExternalProtocolObserver;
 class FaviconTabHelper;
@@ -266,9 +265,11 @@ class TabContentsWrapper : public content::WebContentsObserver {
   // Per-tab observers ---------------------------------------------------------
   // (These provide no API for callers; objects that need to exist 1:1 with tabs
   // and silently do their thing live here.)
+  // WARNING: There is no TabContentsWrapper for extension popups/bubbles and

[Aaron Boodman, 2012/05/25 19:27:42]

This might be too much, but...

// WARNING: Not every place where HTML can run has a 
// TabContentsWrapper. This class is *only* used in a 
// visible, actual, tab inside a browser. Examples of things
// that do not have tab wrappers include:
//
// - Extension background pages and popup bubbles
// - HTML notification bubbles
// - Screensavers on Chrome OS
// - Other random places we decide to display HTML over time
//
// Consider carefully whether your feature is something that
// makes sense only when a tab is displayed, or could make
// sense in other cases we use HTML. It may makes sense to push 
// down into WebContents and make configurable, or at least to
// make easy for other WebContents hosts to include and support.

[Avi (use Gerrit), 2012/05/25 19:49:52]

I actually love this comment, though it would be better to put it higher-up in
the file.

[benjhayden, 2012/05/25 20:41:17]

Done.

[benjhayden, 2012/05/25 20:41:17]

Done.

+  // other raw WebContents. If you want anything to happen for both tabs and raw
+  // WebContents, don't put it here!
 
   scoped_ptr<AlternateErrorPageTabObserver> alternate_error_page_tab_observer_;
-  scoped_ptr<DownloadRequestLimiterObserver> download_request_limiter_observer_;
   scoped_ptr<extensions::WebNavigationTabObserver> webnavigation_observer_;
   scoped_ptr<ExternalProtocolObserver> external_protocol_observer_;
   scoped_ptr<OmniboxSearchHint> omnibox_search_hint_;