Delete obviously unneeded forward declarations in chrome/browser/*.h.

chrome/test/testing_browser_process.h

Index: chrome/test/testing_browser_process.h
diff --git a/chrome/test/testing_browser_process.h b/chrome/test/testing_browser_process.h
index abbd17956f082aaea9dcfe9e566487b768ddd641..82db3af0fae7650c06c6e1d597fe9393ae5c4e90 100644
--- a/chrome/test/testing_browser_process.h
+++ b/chrome/test/testing_browser_process.h
@@ -75,10 +75,6 @@ class TestingBrowserProcess : public BrowserProcess {
     return NULL;
   }
 
-  virtual WebAppInstallerService* web_app_installer_service() {
-    return NULL;
-  }
-
   virtual IconManager* icon_manager() {
     return NULL;
   }