Clarify that WebContents::GetLastCommittedURL returns the virtual URL.

content/public/browser/web_contents.h

 // Copyright (c) 2012 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #ifndef CONTENT_PUBLIC_BROWSER_WEB_CONTENTS_H_
 #define CONTENT_PUBLIC_BROWSER_WEB_CONTENTS_H_
 
 #include <stdint.h>
 
 #include <set>
@@ skipping 192 matching lines @@
   // |GetLastCommittedURL| as appropriate.
   virtual const GURL& GetURL() const = 0;
 
   // Gets the URL currently being displayed in the URL bar, if there is one.
   // This URL might be a pending navigation that hasn't committed yet, so it is
   // not guaranteed to match the current page in this WebContents. A typical
   // example of this is interstitials, which show the URL of the new/loading
   // page (active) but the security context is of the old page (last committed).
   virtual const GURL& GetVisibleURL() const = 0;
 
-  // Gets the last committed URL. It represents the current page that is
-  // displayed in this WebContents. It represents the current security
-  // context.
+  // Gets the last committed URL. This is the URL that would be displayed in the

[Charlie Reis, 2016/06/20 17:33:06]

We probably want to be more explicit about the difference between "visible,"
"virtual," and "displayed," relative to GetVisibleURL.

Instead, let's say:
Gets the virtual URL of the last committed page in this WebContents.  Virtual
URLs are meant to be displayed to the user (e.g., they include the
"view-source:" prefix for view source URLs, unlike NavigationEntry::GetURL). 
The last committed page is the current security context and the content that is
actually displayed within the tab.  See also GetVisibleURL above, which may
differ from this URL.

And let's update the beginning of the GetVisibleURL comment to say:
Gets the virtual URL currently being displayed...

[dominickn, 2016/06/20 23:56:06]

Done.

+  // URL bar for the current page displayed in this WebContents. It represents
+  // the current security context.
   virtual const GURL& GetLastCommittedURL() const = 0;
 
   // Return the currently active RenderProcessHost and RenderViewHost. Each of
   // these may change over time.
   virtual RenderProcessHost* GetRenderProcessHost() const = 0;
 
   // Returns the main frame for the currently active view.
   virtual RenderFrameHost* GetMainFrame() = 0;
 
   // Returns the focused frame for the currently active view.
@@ skipping 522 matching lines @@
 
  private:
   // This interface should only be implemented inside content.
   friend class WebContentsImpl;
   WebContents() {}
 };
 
 }  // namespace content
 
 #endif  // CONTENT_PUBLIC_BROWSER_WEB_CONTENTS_H_