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

7 files changed, 48 insertions, 18 deletions

diff --git a/ash/magnifier/magnifier_constants.h b/ash/magnifier/magnifier_constants.h
index 4ca4c89..aa7cac7 100644
--- a/ash/magnifier/magnifier_constants.h
+++ b/ash/magnifier/magnifier_constants.h
@@ -7,12 +7,16 @@
 
 namespace ash {
 
+// Note: Do not change these values; UMA and prefs depend on them.
 enum MagnifierType {
-  MAGNIFIER_OFF,
-  MAGNIFIER_FULL,
-  MAGNIFIER_PARTIAL,
+  MAGNIFIER_FULL    = 1,
+  MAGNIFIER_PARTIAL = 2,
 };
 
+const int kMaxMagnifierType = 2;
+
+const MagnifierType kDefaultMagnifierType = MAGNIFIER_FULL;
+
 }  // namespace ash
 
 #endif  // ASH_MAGNIFIER_MAGNIFIER_CONSTANTS_H_
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);
diff --git a/ash/shell_delegate.h b/ash/shell_delegate.h
index bdd3958..6a9dd08 100644
--- a/ash/shell_delegate.h
+++ b/ash/shell_delegate.h
@@ -149,8 +149,14 @@ class ASH_EXPORT ShellDelegate {
   // Returns true if high contrast mode is enabled.
   virtual bool IsHighContrastEnabled() const = 0;
 
-  // Invoked to change the mode of the screen magnifier.
-  virtual void SetMagnifier(MagnifierType type) = 0;
+  // Invoked to enable the screen magnifier.
+  virtual void SetMagnifierEnabled(bool enabled) = 0;
+
+  // Invoked to change the type of the screen magnifier.
+  virtual void SetMagnifierType(MagnifierType type) = 0;
+
+  // Returns if the screen magnifier is enabled or not.
+  virtual bool IsMagnifierEnabled() const = 0;
 
   // Returns the current screen magnifier mode.
   virtual MagnifierType GetMagnifierType() const = 0;
diff --git a/ash/system/tray_accessibility.cc b/ash/system/tray_accessibility.cc
index 9b1d261..b64671a 100644
--- a/ash/system/tray_accessibility.cc
+++ b/ash/system/tray_accessibility.cc
@@ -44,7 +44,7 @@ uint32 GetAccessibilityState() {
     state |= A11Y_SPOKEN_FEEDBACK;
   if (shell_delegate->IsHighContrastEnabled())
     state |= A11Y_HIGH_CONTRAST;
-  if (shell_delegate->GetMagnifierType() != ash::MAGNIFIER_OFF)
+  if (shell_delegate->IsMagnifierEnabled())
     state |= A11Y_SCREEN_MAGNIFIER;
   return state;
 }
@@ -138,8 +138,7 @@ void AccessibilityDetailedView::AppendAccessibilityList() {
           IDS_ASH_STATUS_TRAY_ACCESSIBILITY_HIGH_CONTRAST_MODE),
       high_contrast_enabled_ ? gfx::Font::BOLD : gfx::Font::NORMAL,
       high_contrast_enabled_);
-  screen_magnifier_enabled_ =
-      shell_delegate->GetMagnifierType() == ash::MAGNIFIER_FULL;
+  screen_magnifier_enabled_ = shell_delegate->IsMagnifierEnabled();
   screen_magnifier_view_ = AddScrollListItem(
       bundle.GetLocalizedString(
           IDS_ASH_STATUS_TRAY_ACCESSIBILITY_SCREEN_MAGNIFIER),
@@ -198,10 +197,7 @@ void AccessibilityDetailedView::ClickedOn(views::View* sender) {
   } else if (sender == high_contrast_view_) {
     shell_delegate->ToggleHighContrast();
   } else if (sender == screen_magnifier_view_) {
-    bool screen_magnifier_enabled =
-        shell_delegate->GetMagnifierType() == ash::MAGNIFIER_FULL;
-    shell_delegate->SetMagnifier(
-        screen_magnifier_enabled ? ash::MAGNIFIER_OFF : ash::MAGNIFIER_FULL);
+    shell_delegate->SetMagnifierEnabled(!shell_delegate->IsMagnifierEnabled());
   }
 }
 
diff --git a/ash/test/test_shell_delegate.cc b/ash/test/test_shell_delegate.cc
index f782c86..c2fdc60 100644
--- a/ash/test/test_shell_delegate.cc
+++ b/ash/test/test_shell_delegate.cc
@@ -24,7 +24,8 @@ TestShellDelegate::TestShellDelegate()
       session_started_(true),
       spoken_feedback_enabled_(false),
       high_contrast_enabled_(false),
-      screen_magnifier_type_(MAGNIFIER_OFF),
+      screen_magnifier_enabled_(false),
+      screen_magnifier_type_(kDefaultMagnifierType),
       user_logged_in_(true),
       can_lock_screen_(true),
       num_exit_requests_(0) {
@@ -124,10 +125,18 @@ bool TestShellDelegate::IsHighContrastEnabled() const {
   return high_contrast_enabled_;
 }
 
-void TestShellDelegate::SetMagnifier(const MagnifierType type) {
+void TestShellDelegate::SetMagnifierEnabled(bool enabled) {
+  screen_magnifier_enabled_ = enabled;
+}
+
+void TestShellDelegate::SetMagnifierType(MagnifierType type) {
   screen_magnifier_type_ = type;
 }
 
+bool TestShellDelegate::IsMagnifierEnabled() const {
+  return screen_magnifier_enabled_;
+}
+
 MagnifierType TestShellDelegate::GetMagnifierType() const {
   return screen_magnifier_type_;
 }
diff --git a/ash/test/test_shell_delegate.h b/ash/test/test_shell_delegate.h
index f7bb171..76add5d 100644
--- a/ash/test/test_shell_delegate.h
+++ b/ash/test/test_shell_delegate.h
@@ -45,7 +45,9 @@ class TestShellDelegate : public 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;
@@ -94,6 +96,7 @@ class TestShellDelegate : public ShellDelegate {
   bool session_started_;
   bool spoken_feedback_enabled_;
   bool high_contrast_enabled_;
+  bool screen_magnifier_enabled_;
   MagnifierType screen_magnifier_type_;
   bool user_logged_in_;
   bool can_lock_screen_;