Simplify decidePolicyForNavigation + remove POST-only-in-http(s) DCHECK.

content/renderer/render_frame_impl.cc

Index: content/renderer/render_frame_impl.cc
diff --git a/content/renderer/render_frame_impl.cc b/content/renderer/render_frame_impl.cc
index 2f419abd1c281a6440243692b8bf1172c357a28d..d6c00542a565cd05d80cf6e45b150c1dc37bb5e6 100644
--- a/content/renderer/render_frame_impl.cc
+++ b/content/renderer/render_frame_impl.cc
@@ -4985,12 +4985,10 @@ WebNavigationPolicy RenderFrameImpl::decidePolicyForNavigation(
                         info.navigationType != blink::WebNavigationTypeReload);
 
     if (!should_fork && url.SchemeIs(url::kFileScheme)) {
-      // Fork non-file to file opens.  Check the opener URL if this is the
-      // initial navigation in a newly opened window.
-      GURL source_url(old_url);
-      if (is_initial_navigation && source_url.is_empty() && frame_->opener())
-        source_url = frame_->opener()->top()->document().url();
-      should_fork = !source_url.SchemeIs(url::kFileScheme);
+      // Fork non-file to file opens.  Note that this may fork unnecessarily if
+      // another tab (hosting a file or not) targeted this one before its
+      // initial navigation, but that shouldn't cause a problem.
+      should_fork = !old_url.SchemeIs(url::kFileScheme);

[Łukasz Anforowicz, 2016/07/20 22:23:04]

The changes above [should] just replicate the changes that have been suggested
and implemented in patchset #2 of
https://codereview.chromium.org/2153573002/#msg4.

     }
 
     if (!should_fork) {