Allow enhanced bookmarks external component extensions to be disabled

Allow enhanced bookmarks external component extensions to be
disabled/uninstalled. This facilitates ongoing development and testing
of multiple versions of extensions that are ultimately released as
external component extensions.

BUG=401315

Review URL: https://codereview.chromium.org/445233002

Cr-Commit-Position: refs/heads/master@{#289270}
git-svn-id: svn://svn.chromium.org/chrome/trunk/src@289270 0039d316-1c4b-4281-b951-d872f2087c98

chrome/browser/extensions/external_component_loader.cc

@@ -5,6 +5,8 @@
 #include "chrome/browser/extensions/external_component_loader.h"
 
 #include "base/command_line.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/signin/signin_manager_factory.h"
@@ -34,6 +36,24 @@ 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;

chrome/browser/extensions/external_component_loader.h

@@ -13,6 +13,8 @@
 
 namespace extensions {
 
+class Extension;
+
 // A specialization of the ExternalLoader that loads a hard-coded list of
 // external extensions, that should be considered components of chrome (but
 // unlike Component extensions, these extensions are installed from the webstore
@@ -23,6 +25,9 @@ class ExternalComponentLoader : public ExternalLoader {
  public:
   explicit ExternalComponentLoader(Profile* profile);
 
+  // True if |extension| should be modifiable by the user.
+  static bool IsModifiable(const extensions::Extension* extension);
+
  protected:
   virtual void StartLoading() OVERRIDE;
 

chrome/browser/extensions/standard_management_policy_provider.cc

@@ -6,6 +6,7 @@
 
 #include "base/prefs/pref_service.h"
 #include "chrome/browser/extensions/blacklist.h"
+#include "chrome/browser/extensions/external_component_loader.h"
 #include "chrome/common/pref_names.h"
 #include "extensions/browser/admin_policy.h"
 #include "extensions/browser/extension_prefs.h"
@@ -54,13 +55,17 @@ bool StandardManagementPolicyProvider::UserMayLoad(
 bool StandardManagementPolicyProvider::UserMayModifySettings(
     const Extension* extension,
     base::string16* error) const {
-  return admin_policy::UserMayModifySettings(extension, error);
+  return admin_policy::UserMayModifySettings(extension, error) ||
+         (extension->location() == extensions::Manifest::EXTERNAL_COMPONENT &&
+          ExternalComponentLoader::IsModifiable(extension));
 }
 
 bool StandardManagementPolicyProvider::MustRemainEnabled(
     const Extension* extension,
     base::string16* error) const {
-  return admin_policy::MustRemainEnabled(extension, error);
+  return admin_policy::MustRemainEnabled(extension, error) ||
+         (extension->location() == extensions::Manifest::EXTERNAL_COMPONENT &&
+          ExternalComponentLoader::IsModifiable(extension));
 }
 
 }  // namespace extensions