Cache --whitelisted-extension-id in SimpleFeature.

extensions/common/features/simple_feature.cc

Index: extensions/common/features/simple_feature.cc
diff --git a/extensions/common/features/simple_feature.cc b/extensions/common/features/simple_feature.cc
index 6a5bece485df46b7ccc9db8ef21c5d62a521ba93..15fd4776664169a5b2f9ed7b60ac6e71ffdce303 100644
--- a/extensions/common/features/simple_feature.cc
+++ b/extensions/common/features/simple_feature.cc
@@ -11,6 +11,7 @@
 #include "base/bind.h"
 #include "base/command_line.h"
 #include "base/debug/alias.h"
+#include "base/macros.h"
 #include "base/sha1.h"
 #include "base/stl_util.h"
 #include "base/strings/string_number_conversions.h"
@@ -222,6 +223,17 @@ bool IsCommandLineSwitchEnabled(const std::string& switch_name) {
   return false;
 }
 
+bool IsWhitelistedByCommandLine(const std::string& extension_id) {
+  // A singleton copy of the --whitelisted-extension-id so that we don't need to
+  // copy it from the CommandLine each time.
+  CR_DEFINE_STATIC_LOCAL(
+      std::string, whitelisted_extension_id,
+      (base::CommandLine::ForCurrentProcess()->GetSwitchValueASCII(

[not at google - send to devlin, 2015/03/31 17:16:05]

why are the parens around the base::CommandLine... call necessary? looks a bit
odd.

[jackhou1, 2015/03/31 21:53:41]

The macro is just:
#define CR_DEFINE_STATIC_LOCAL(type, name, arguments) \
  static type& name = *new type arguments

so the () in |arguments| becomes part of the constructor syntax.

[not at google - send to devlin, 2015/03/31 22:10:04]

Well, that's silly. Macros are supposed to put parens around expressions
themselves. The CR_DEFINE_STATIC_LOCAL macro should be fixed.

[jackhou1, 2015/03/31 22:19:18]

Yeah probably, looks like it was originally copied from WebKit, so I can't tell
if there was a good reason for it.

+          switches::kWhitelistedExtensionID)));
+  return !whitelisted_extension_id.empty() &&
+         whitelisted_extension_id == extension_id;
+}
+
 }  // namespace
 
 struct SimpleFeature::Mappings {
@@ -363,20 +375,9 @@ Feature::Availability SimpleFeature::IsAvailableToManifest(
   if (component_extensions_auto_granted_ && location == Manifest::COMPONENT)
     return CreateAvailability(IS_AVAILABLE, type);
 
-  if (!whitelist_.empty()) {
-    if (!IsIdInWhitelist(extension_id)) {
-      // TODO(aa): This is gross. There should be a better way to test the
-      // whitelist.
-      base::CommandLine* command_line = base::CommandLine::ForCurrentProcess();
-      if (!command_line->HasSwitch(switches::kWhitelistedExtensionID))
-        return CreateAvailability(NOT_FOUND_IN_WHITELIST, type);
-
-      std::string whitelist_switch_value =
-          base::CommandLine::ForCurrentProcess()->GetSwitchValueASCII(
-              switches::kWhitelistedExtensionID);
-      if (extension_id != whitelist_switch_value)
-        return CreateAvailability(NOT_FOUND_IN_WHITELIST, type);
-    }
+  if (!whitelist_.empty() && !IsIdInWhitelist(extension_id) &&
+      !IsWhitelistedByCommandLine(extension_id)) {
+    return CreateAvailability(NOT_FOUND_IN_WHITELIST, type);
   }
 
   if (!MatchesManifestLocation(location))