Allow enhanced bookmarks external component extensions to be disabled

chrome/browser/extensions/external_component_loader.cc

Index: chrome/browser/extensions/external_component_loader.cc
diff --git a/chrome/browser/extensions/external_component_loader.cc b/chrome/browser/extensions/external_component_loader.cc
index 10eb0ec145c2570f7f632cc244533d967576b44e..39e65d15b216bbad1b5fed9e03a5f415c0e43c04 100644
--- a/chrome/browser/extensions/external_component_loader.cc
+++ b/chrome/browser/extensions/external_component_loader.cc
@@ -4,6 +4,8 @@
 
 #include "chrome/browser/extensions/external_component_loader.h"
 
+#include "base/sha1.h"
+#include "base/strings/string_number_conversions.h"
 #include "chrome/browser/bookmarks/enhanced_bookmarks_features.h"
 #include "chrome/browser/browser_process.h"
 #include "chrome/browser/search/hotword_service_factory.h"
@@ -28,6 +30,24 @@ ExternalComponentLoader::ExternalComponentLoader(Profile* profile)
 
 ExternalComponentLoader::~ExternalComponentLoader() {}
 
+// static
+bool ExternalComponentLoader::IsModifiable(
+    const extensions::Extension* extension) {
+  if (extension->location() == extensions::Manifest::EXTERNAL_COMPONENT) {
+    static const char* enhanced_extension_hashes[] = {
+        "D5736E4B5CF695CB93A2FB57E4FDC6E5AFAB6FE2",  // http://crbug.com/312900
+        "D57DE394F36DC1C3220E7604C575D29C51A6C495",  // http://crbug.com/319444
+        "3F65507A3B39259B38C8173C6FFA3D12DF64CCE9"   // http://crbug.com/371562
+    };
+    std::string hash = base::SHA1HashString(extension->id());
+    hash = base::HexEncode(hash.c_str(), hash.length());
+    for (size_t i = 0; i < arraysize(enhanced_extension_hashes); i++)
+      if (hash == enhanced_extension_hashes[i])
+        return true;
+  }
+  return false;
+}
+
 void ExternalComponentLoader::StartLoading() {
   prefs_.reset(new base::DictionaryValue());
   std::string appId = extension_misc::kInAppPaymentsSupportAppId;