Introduces an additional extension loader that load extra extensions based on per-extension json fi…

chrome/common/chrome_paths.cc

Index: chrome/common/chrome_paths.cc
===================================================================
--- chrome/common/chrome_paths.cc	(revision 132213)
+++ chrome/common/chrome_paths.cc	(working copy)
@@ -71,6 +71,18 @@
     FILE_PATH_LITERAL("pepper/libppgoogletalk.so");
 
 #endif  // defined(OS_POSIX) && !defined(OS_MACOSX)
+
+#if defined(OS_LINUX)
+// The search path that contains information about per-extension
+// definition files.

[Sam Kerner (Chrome), 2012/04/13 19:35:13]

A comment with a link to a standard will help avoid a flamewar when a specific
linux distribution demands that we use their preferred path :)

You mentioned http://www.pathname.com/fhs/ , which seems like a good choice.

[Alexandre Abreu, 2012/04/13 21:52:38]

Done.

+const char kFilepathSinglePrefExtensions[] =
+#if defined(GOOGLE_CHROME_BUILD)
+    FILE_PATH_LITERAL("/usr/share/google-chrome/extensions");
+#else
+    FILE_PATH_LITERAL("/usr/share/chromium/extensions");
+#endif
+#endif  // defined(OS_LINUX)
+
 }  // namespace
 
 namespace chrome {
@@ -364,6 +376,12 @@
       break;
     }
 #endif
+    case chrome::DIR_SINGLE_EXTERNAL_EXTENSIONS: {
+#if defined(OS_LINUX)
+      cur = FilePath(FILE_PATH_LITERAL(kFilepathSinglePrefExtensions));
+#endif
+      break;
+    }
     case chrome::DIR_EXTERNAL_EXTENSIONS:
 #if defined(OS_MACOSX)
       if (!chrome::GetGlobalApplicationSupportDirectory(&cur))