Re-land alexbost's experimental offscreenTabs API.

chrome/browser/extensions/extension_tab_util.h

Index: chrome/browser/extensions/extension_tab_util.h
diff --git a/chrome/browser/extensions/extension_tab_util.h b/chrome/browser/extensions/extension_tab_util.h
index 5a2fe7798472d2c91cf69222beeb1347754ef127..ed11e2c6955ed7fc36672091ee781a363233f51d 100644
--- a/chrome/browser/extensions/extension_tab_util.h
+++ b/chrome/browser/extensions/extension_tab_util.h
@@ -9,6 +9,8 @@
 #include <string>
 
 class Browser;
+class Extension;
+class GURL;
 class Profile;
 class TabContents;
 class TabContentsWrapper;
@@ -62,6 +64,20 @@ class ExtensionTabUtil {
                          TabStripModel** tab_strip,
                          TabContentsWrapper** contents,
                          int* tab_index);
+
+  // Takes |url_string| and returns a GURL which is either valid and absolute
+  // or invalid. If |url_string| is not directly interpretable as a valid (it is
+  // likely a relative URL) an attempt is made to resolve it. |extension| is
+  // provided so it can be resolved relative to its extension base
+  // (chrome-extension://<id>/). Using the source frame url would be more
+  // correct, but because the api shipped with urls resolved relative to their
+  // extension base, we decided it wasn't worth breaking existing extensions to
+  // fix.
+  static GURL ResolvePossiblyRelativeURL(const std::string& url_string,
+                                         const Extension* extension);
+
+  // Returns true if |url| is used for testing crashes.
+  static bool IsCrashURL(const GURL& url);
 };
 
 #endif  // CHROME_BROWSER_EXTENSIONS_EXTENSION_TAB_UTIL_H__