Re-introduce the partial magnifier

Major Changes:
- Adding a selectbox at the right of screen magnifier setting on the setting page.
- Adding 'screen_magnifier_type2' pref.
- Separating the enable/disable state of magnifier from MagnifierType. MagnifierType does no longer indicate the current enable/disable status.
- Add IsMagnifierEnabled() to shell delegate.

BUG=166832
TEST=confirm that magnifier can be enabled/disabled via the tray and the settings page. browser_test passes.

R=zork@chromium.org, derat@chromium.org, nkostylev@chromium.org
TBR=jhawkins@chromium.org
# TBRing for small changed in C/B/ui/webui/options/ and C/B/resources/options/

Review URL: https://chromiumcodereview.appspot.com/11642014

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@176087 0039d316-1c4b-4281-b951-d872f2087c98

2 files changed, 15 insertions, 3 deletions

diff --git a/ash/shell/shell_delegate_impl.cc b/ash/shell/shell_delegate_impl.cc
index fde2bd1..681dfb5 100644
--- a/ash/shell/shell_delegate_impl.cc
+++ b/ash/shell/shell_delegate_impl.cc
@@ -25,7 +25,8 @@ ShellDelegateImpl::ShellDelegateImpl()
       locked_(false),
       spoken_feedback_enabled_(false),
       high_contrast_enabled_(false),
-      screen_magnifier_type_(MAGNIFIER_OFF) {
+      screen_magnifier_enabled_(false),
+      screen_magnifier_type_(kDefaultMagnifierType) {
 }
 
 ShellDelegateImpl::~ShellDelegateImpl() {
@@ -134,10 +135,18 @@ bool ShellDelegateImpl::IsHighContrastEnabled() const {
   return high_contrast_enabled_;
 }
 
-void ShellDelegateImpl::SetMagnifier(MagnifierType type) {
+void ShellDelegateImpl::SetMagnifierEnabled(bool enabled) {
+  screen_magnifier_enabled_ = enabled;
+}
+
+void ShellDelegateImpl::SetMagnifierType(MagnifierType type) {
   screen_magnifier_type_ = type;
 }
 
+bool ShellDelegateImpl::IsMagnifierEnabled() const {
+  return screen_magnifier_enabled_;
+}
+
 MagnifierType ShellDelegateImpl::GetMagnifierType() const {
   return screen_magnifier_type_;
 }
diff --git a/ash/shell/shell_delegate_impl.h b/ash/shell/shell_delegate_impl.h
index 3a987e2..e94d08a 100644
--- a/ash/shell/shell_delegate_impl.h
+++ b/ash/shell/shell_delegate_impl.h
@@ -46,7 +46,9 @@ class ShellDelegateImpl : public ash::ShellDelegate {
   virtual bool IsSpokenFeedbackEnabled() const OVERRIDE;
   virtual void ToggleHighContrast() OVERRIDE;
   virtual bool IsHighContrastEnabled() const OVERRIDE;
-  virtual void SetMagnifier(MagnifierType type) OVERRIDE;
+  virtual void SetMagnifierEnabled(bool enabled) OVERRIDE;
+  virtual void SetMagnifierType(MagnifierType type) OVERRIDE;
+  virtual bool IsMagnifierEnabled() const OVERRIDE;
   virtual MagnifierType GetMagnifierType() const OVERRIDE;
   virtual bool ShouldAlwaysShowAccessibilityMenu() const OVERRIDE;
   virtual app_list::AppListViewDelegate* CreateAppListViewDelegate() OVERRIDE;
@@ -79,6 +81,7 @@ class ShellDelegateImpl : public ash::ShellDelegate {
   bool locked_;
   bool spoken_feedback_enabled_;
   bool high_contrast_enabled_;
+  bool screen_magnifier_enabled_;
   MagnifierType screen_magnifier_type_;
 
   DISALLOW_COPY_AND_ASSIGN(ShellDelegateImpl);