Reintroduce --prompt-for-external-extensions flag on Chromium builds.

extensions/common/switches.cc

Index: extensions/common/switches.cc
diff --git a/extensions/common/switches.cc b/extensions/common/switches.cc
index 51681cc2ce33e0306f07fe6016114203de0edaa3..5c74866c6311f4ef654f67e3ce420dc03343c449 100644
--- a/extensions/common/switches.cc
+++ b/extensions/common/switches.cc
@@ -87,6 +87,12 @@ const char kScriptsRequireAction[] = "scripts-require-action";
 // as --scripts-require-action=1.
 const char kEnableScriptsRequireAction[] = "enable-scripts-require-action";
 
+#if defined(CHROMIUM_BUILD)
+// Should we prompt the user before allowing external extensions to install?
+// This flag is enabled on Chromium for testing purposes.

[robliao, 2015/07/27 21:56:16]

My reading is that the flag is available for use in Chromium builds and is only
enabled by default for Windows. Is this correct?

[sydli, 2015/07/27 22:06:18]

Yes, right now the prompt is enabled by default on Windows, and apparently will
be on Mac soon. Making the flag available on Chromium builds ensures tests that
auto-install extensions work on both.

[robliao, 2015/07/27 22:13:47]

Gotcha. Let's do s/enabled/available/ then.

[sydli, 2015/07/27 22:21:50]

Sounds good! Done.

+const char kPromptForExternalExtensions[] = "prompt-for-external-extensions";
+#endif
+
 // Makes component extensions appear in chrome://settings/extensions.
 const char kShowComponentExtensionOptions[] =
     "show-component-extension-options";