Re-land alexbost's experimental offscreenTabs API.

Original code review: http://codereview.chromium.org/7720002/
A followup code review: http://chromiumcodereview.appspot.com/9150052/

This includes some refactoring to simplify and reduce the code size:
- sharing more code between tabs and offscreenTabs
- splitting up and fixing the browser tests
- forbidding use of the API from a background page

BUG=110833
TEST=OffscreenTabsApiTest.*

Review URL: https://chromiumcodereview.appspot.com/9813014

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@128037 0039d316-1c4b-4281-b951-d872f2087c98

1 files changed, 22 insertions, 0 deletions

diff --git a/chrome/browser/extensions/extension_tab_util.cc b/chrome/browser/extensions/extension_tab_util.cc
index 98bd098..9f91a3a 100644
--- a/chrome/browser/extensions/extension_tab_util.cc
+++ b/chrome/browser/extensions/extension_tab_util.cc
@@ -12,9 +12,13 @@
 #include "chrome/browser/ui/browser_list.h"
 #include "chrome/browser/sessions/restore_tab_helper.h"
 #include "chrome/browser/extensions/extension_tabs_module_constants.h"
+#include "chrome/browser/net/url_fixer_upper.h"
+#include "chrome/common/extensions/extension.h"
+#include "chrome/common/url_constants.h"
 #include "content/public/browser/favicon_status.h"
 #include "content/public/browser/navigation_entry.h"
 #include "content/public/browser/web_contents.h"
+#include "googleurl/src/gurl.h"
 
 namespace keys = extension_tabs_module_constants;
 namespace errors = extension_manifest_errors;
@@ -223,3 +227,21 @@ bool ExtensionTabUtil::GetTabById(int tab_id,
   }
   return false;
 }
+
+GURL ExtensionTabUtil::ResolvePossiblyRelativeURL(const std::string& url_string,
+                                                  const Extension* extension) {
+  GURL url = GURL(url_string);
+  if (!url.is_valid())
+    url = extension->GetResourceURL(url_string);
+
+  return url;
+}
+
+bool ExtensionTabUtil::IsCrashURL(const GURL& url) {
+  // Check a fixed-up URL, to normalize the scheme and parse hosts correctly.
+  GURL fixed_url =
+      URLFixerUpper::FixupURL(url.possibly_invalid_spec(), std::string());
+  return (fixed_url.SchemeIs(chrome::kChromeUIScheme) &&
+          (fixed_url.host() == chrome::kChromeUIBrowserCrashHost ||
+           fixed_url.host() == chrome::kChromeUICrashHost));
+}