Make browser_handles_top_level_requests synchronous.

chrome/browser/external_tab/external_tab_container_win.cc

Index: chrome/browser/external_tab/external_tab_container_win.cc
diff --git a/chrome/browser/external_tab/external_tab_container_win.cc b/chrome/browser/external_tab/external_tab_container_win.cc
index d76005913fd9cfc9842ff594cf1692403f42506f..b0dfd7b288d52d6c121675d37abbdf1b42571baa 100644
--- a/chrome/browser/external_tab/external_tab_container_win.cc
+++ b/chrome/browser/external_tab/external_tab_container_win.cc
@@ -408,6 +408,23 @@ WebContents* ExternalTabContainer::OpenURLFromTab(WebContents* source,
   return NULL;
 }
 
+bool ExternalTabContainer::ShouldIgnoreNavigation(
+    WebContents* source,
+    const GURL& url,
+    const content::Referrer& referrer,
+    WindowOpenDisposition disposition,
+    bool is_content_intiated,

[Charlie Reis, 2012/04/05 17:06:53]

nit: initiated

[mkosiba (inactive), 2012/04/10 17:58:37]

Done.

+    content::PageTransition transition_type) {
+  // This will make every navigation browser-initiated.
+  // TODO: Investigate modifying ExternalTabContainer to work without canceling
+  // and re-issuing every navigation.

[Charlie Reis, 2012/04/05 17:06:53]

This TODO seems critical.  We can't treat every link click as a
browser-initiated navigation.  That would introduce process swaps for every type
of cross-site navigation, which would break script connections between tabs in
real cases.  We're currently very careful about when we use process swaps for
this reason-- see the Caveats section of this page for details:
http://dev.chromium.org/developers/design-documents/process-models

(Note: as mentioned below, I'm not sure when this class is used, so I'm not sure
how often this problem will arise.)

[mkosiba (inactive), 2012/04/10 17:58:37]

This is exactly how browser_handles_top_level_requests works now - every link
click is forced to be a browser-initiated navigation (take a look at the code in
decidePolicyForNavigation).

The reason I'm not making more changes here is because I'm assuming
ExternalTabContainer clients are depending on this behavior (pessimistic
assumption - I don't know this for a fact)

+
+  if (is_content_intiated)
+    source->GetController().LoadURL(url, referrer, transition_type,
+                                    std::string());
+  return true;
+}
+
 void ExternalTabContainer::NavigationStateChanged(const WebContents* source,
                                                   unsigned changed_flags) {
   if (automation_) {