Move FeatureSwitch to top-level extensions/

Move FeatureSwitch to extensions/common/
Move the switches used in FeatureSwitch to extensions/common/switches.h (when necessary).
Update some uses of the switches to use feature switch instead of the commandline

BUG=159265
TBR=rdsmith@chromium.org (c/b/download)
TBR=sky@chromium.org (c/b/ui/, c/test/ui/)

Review URL: https://codereview.chromium.org/47923018

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@233977 0039d316-1c4b-4281-b951-d872f2087c98

5 files changed, 253 insertions, 2 deletions

diff --git a/extensions/common/feature_switch.cc b/extensions/common/feature_switch.cc
new file mode 100644
index 0000000..0024461
--- /dev/null
+++ b/extensions/common/feature_switch.cc
@@ -0,0 +1,146 @@
+// Copyright 2013 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#include "extensions/common/feature_switch.h"
+
+#include "base/command_line.h"
+#include "base/lazy_instance.h"
+#include "base/metrics/field_trial.h"
+#include "base/strings/string_util.h"
+#include "extensions/common/switches.h"
+
+namespace extensions {
+
+namespace {
+
+class CommonSwitches {
+ public:
+  CommonSwitches()
+      : easy_off_store_install(
+            switches::kEasyOffStoreExtensionInstall,
+            FeatureSwitch::DEFAULT_DISABLED),
+        global_commands(
+            switches::kGlobalCommands,
+            FeatureSwitch::DEFAULT_DISABLED),
+        script_badges(
+            switches::kScriptBadges,
+            FeatureSwitch::DEFAULT_DISABLED),
+        script_bubble(
+            switches::kScriptBubble,
+            FeatureSwitch::DEFAULT_DISABLED),
+        prompt_for_external_extensions(
+            switches::kPromptForExternalExtensions,
+#if defined(OS_WIN)
+            FeatureSwitch::DEFAULT_ENABLED),
+#else
+            FeatureSwitch::DEFAULT_DISABLED),
+#endif
+        error_console(
+            switches::kErrorConsole,
+            FeatureSwitch::DEFAULT_DISABLED) {}
+
+  FeatureSwitch easy_off_store_install;
+  FeatureSwitch global_commands;
+  FeatureSwitch script_badges;
+  FeatureSwitch script_bubble;
+  FeatureSwitch prompt_for_external_extensions;
+  FeatureSwitch error_console;
+};
+
+base::LazyInstance<CommonSwitches> g_common_switches =
+    LAZY_INSTANCE_INITIALIZER;
+
+}  // namespace
+
+FeatureSwitch* FeatureSwitch::easy_off_store_install() {
+  return &g_common_switches.Get().easy_off_store_install;
+}
+FeatureSwitch* FeatureSwitch::global_commands() {
+  return &g_common_switches.Get().global_commands;
+}
+FeatureSwitch* FeatureSwitch::script_badges() {
+  return &g_common_switches.Get().script_badges;
+}
+FeatureSwitch* FeatureSwitch::script_bubble() {
+  return &g_common_switches.Get().script_bubble;
+}
+FeatureSwitch* FeatureSwitch::prompt_for_external_extensions() {
+  return &g_common_switches.Get().prompt_for_external_extensions;
+}
+FeatureSwitch* FeatureSwitch::error_console() {
+  return &g_common_switches.Get().error_console;
+}
+
+FeatureSwitch::ScopedOverride::ScopedOverride(FeatureSwitch* feature,
+                                              bool override_value)
+    : feature_(feature),
+      previous_value_(feature->GetOverrideValue()) {
+  feature_->SetOverrideValue(
+      override_value ? OVERRIDE_ENABLED : OVERRIDE_DISABLED);
+}
+
+FeatureSwitch::ScopedOverride::~ScopedOverride() {
+  feature_->SetOverrideValue(previous_value_);
+}
+
+FeatureSwitch::FeatureSwitch(const char* switch_name,
+                             DefaultValue default_value) {
+  Init(CommandLine::ForCurrentProcess(), switch_name, default_value);
+}
+
+FeatureSwitch::FeatureSwitch(const CommandLine* command_line,
+                             const char* switch_name,
+                             DefaultValue default_value) {
+  Init(command_line, switch_name, default_value);
+}
+
+void FeatureSwitch::Init(const CommandLine* command_line,
+                         const char* switch_name,
+                         DefaultValue default_value) {
+  command_line_ = command_line;
+  switch_name_ = switch_name;
+  default_value_ = default_value == DEFAULT_ENABLED;
+  override_value_ = OVERRIDE_NONE;
+}
+
+bool FeatureSwitch::IsEnabled() const {
+  if (override_value_ != OVERRIDE_NONE)
+    return override_value_ == OVERRIDE_ENABLED;
+
+  std::string temp = command_line_->GetSwitchValueASCII(switch_name_);
+  std::string switch_value;
+  TrimWhitespaceASCII(temp, TRIM_ALL, &switch_value);
+
+  if (switch_value == "1")
+    return true;
+
+  if (switch_value == "0")
+    return false;
+
+  if (!default_value_ && command_line_->HasSwitch(GetLegacyEnableFlag()))
+    return true;
+
+  if (default_value_ && command_line_->HasSwitch(GetLegacyDisableFlag()))
+    return false;
+
+  return default_value_;
+}
+
+std::string FeatureSwitch::GetLegacyEnableFlag() const {
+  return std::string("enable-") + switch_name_;
+}
+
+std::string FeatureSwitch::GetLegacyDisableFlag() const {
+  return std::string("disable-") + switch_name_;
+}
+
+void FeatureSwitch::SetOverrideValue(OverrideValue override_value) {
+  override_value_ = override_value;
+}
+
+FeatureSwitch::OverrideValue FeatureSwitch::GetOverrideValue() const {
+  return override_value_;
+}
+
+}  // namespace extensions
diff --git a/extensions/common/feature_switch.h b/extensions/common/feature_switch.h
new file mode 100644
index 0000000..ece1b01
--- /dev/null
+++ b/extensions/common/feature_switch.h
@@ -0,0 +1,79 @@
+// Copyright 2013 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#ifndef EXTENSIONS_COMMON_FEATURE_SWITCH_H_
+#define EXTENSIONS_COMMON_FEATURE_SWITCH_H_
+
+#include <string>
+
+#include "base/basictypes.h"
+
+class CommandLine;
+
+namespace extensions {
+
+// A switch that can turn a feature on or off. Typically controlled via
+// command-line switches but can be overridden, e.g., for testing.
+class FeatureSwitch {
+ public:
+  static FeatureSwitch* easy_off_store_install();
+  static FeatureSwitch* global_commands();
+  static FeatureSwitch* script_badges();
+  static FeatureSwitch* script_bubble();
+  static FeatureSwitch* prompt_for_external_extensions();
+  static FeatureSwitch* error_console();
+
+  enum DefaultValue {
+    DEFAULT_ENABLED,
+    DEFAULT_DISABLED
+  };
+
+  enum OverrideValue {
+    OVERRIDE_NONE,
+    OVERRIDE_ENABLED,
+    OVERRIDE_DISABLED
+  };
+
+  // A temporary override for the switch value.
+  class ScopedOverride {
+   public:
+    ScopedOverride(FeatureSwitch* feature, bool override_value);
+    ~ScopedOverride();
+   private:
+    FeatureSwitch* feature_;
+    FeatureSwitch::OverrideValue previous_value_;
+    DISALLOW_COPY_AND_ASSIGN(ScopedOverride);
+  };
+
+  FeatureSwitch(const char* switch_name,
+                DefaultValue default_value);
+  FeatureSwitch(const CommandLine* command_line,
+                const char* switch_name,
+                DefaultValue default_value);
+
+  // Consider using ScopedOverride instead.
+  void SetOverrideValue(OverrideValue value);
+  OverrideValue GetOverrideValue() const;
+
+  bool IsEnabled() const;
+
+  std::string GetLegacyEnableFlag() const;
+  std::string GetLegacyDisableFlag() const;
+
+ private:
+  void Init(const CommandLine* command_line,
+            const char* switch_name,
+            DefaultValue default_value);
+
+  const CommandLine* command_line_;
+  const char* switch_name_;
+  bool default_value_;
+  OverrideValue override_value_;
+
+  DISALLOW_COPY_AND_ASSIGN(FeatureSwitch);
+};
+
+}  // namespace extensions
+
+#endif  // EXTENSIONS_COMMON_FEATURE_SWITCH_H_
diff --git a/extensions/common/switches.cc b/extensions/common/switches.cc
index 674bb03..451cbc0 100644
--- a/extensions/common/switches.cc
+++ b/extensions/common/switches.cc
@@ -16,7 +16,12 @@ const char kAllowLegacyExtensionManifests[] =
 // Allows injecting extensions and user scripts on the extensions gallery
 // site. Normally prevented for security reasons, but can be useful for
 // automation testing of the gallery.
-const char kAllowScriptingGallery[]         = "allow-scripting-gallery";
+const char kAllowScriptingGallery[] = "allow-scripting-gallery";
+
+// Enables extensions to be easily installed from sites other than the web
+// store. Without this flag, they can still be installed, but must be manually
+// dragged onto chrome://extensions/.
+const char kEasyOffStoreExtensionInstall[] = "easy-off-store-extension-install";
 
 // Enables extension APIs that are in development.
 const char kEnableExperimentalExtensionApis[] =
@@ -37,7 +42,21 @@ const char kEventPageSuspendingTime[]       = "event-page-unloading-time";
 // Enables extensions running scripts on chrome:// URLs.
 // Extensions still need to explicitly request access to chrome:// URLs in the
 // manifest.
-const char kExtensionsOnChromeURLs[]        = "extensions-on-chrome-urls";
+const char kExtensionsOnChromeURLs[] = "extensions-on-chrome-urls";
+
+// Enables setting global commands through the Extensions Commands API.
+const char kGlobalCommands[] = "global-commands";
+
+// Should we prompt the user before allowing external extensions to install?
+// Default is yes.
+const char kPromptForExternalExtensions[] = "prompt-for-external-extensions";
+
+// Enables or disables extension scripts badges in the location bar.
+const char kScriptBadges[] = "script-badges";
+
+// Enable or diable the "script bubble" icon in the URL bar that tells you how
+// many extensions are running scripts on a page.
+const char kScriptBubble[] = "script-bubble";
 
 // Makes component extensions appear in chrome://settings/extensions.
 const char kShowComponentExtensionOptions[] =
diff --git a/extensions/common/switches.h b/extensions/common/switches.h
index e6ff310..7111d87 100644
--- a/extensions/common/switches.h
+++ b/extensions/common/switches.h
@@ -13,11 +13,16 @@ namespace switches {
 
 extern const char kAllowLegacyExtensionManifests[];
 extern const char kAllowScriptingGallery[];
+extern const char kEasyOffStoreExtensionInstall[];
 extern const char kEnableExperimentalExtensionApis[];
 extern const char kErrorConsole[];
 extern const char kEventPageIdleTime[];
 extern const char kEventPageSuspendingTime[];
 extern const char kExtensionsOnChromeURLs[];
+extern const char kGlobalCommands[];
+extern const char kPromptForExternalExtensions[];
+extern const char kScriptBadges[];
+extern const char kScriptBubble[];
 extern const char kShowComponentExtensionOptions[];
 
 }  // namespace switches
diff --git a/extensions/extensions.gyp b/extensions/extensions.gyp
index 6cef0ee..be923b6 100644
--- a/extensions/extensions.gyp
+++ b/extensions/extensions.gyp
@@ -47,6 +47,8 @@
         'common/extension_urls.h',
         'common/extensions_client.cc',
         'common/extensions_client.h',
+        'common/feature_switch.cc',
+        'common/feature_switch.h',
         'common/features/feature.cc',
         'common/features/feature.h',
         'common/features/feature_provider.cc',