Use multi-value switch to enable/disable the unified gesture detector.

BUG=332418

Review URL: https://codereview.chromium.org/290733013

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@272652 0039d316-1c4b-4281-b951-d872f2087c98

ui/aura/gestures/gesture_recognizer_unittest.cc

@@ -681,10 +681,10 @@ class GestureRecognizerTest : public AuraTestBase,
 
   virtual void SetUp() OVERRIDE {
     // TODO(tdresser): Once unified GR has landed, only run these tests once.
-    if (UsingUnifiedGR()) {
-      CommandLine::ForCurrentProcess()->AppendSwitch(
-          switches::kUseUnifiedGestureDetector);
-    }
+    CommandLine::ForCurrentProcess()->AppendSwitchASCII(
+        switches::kUnifiedGestureDetector,
+        UsingUnifiedGR() ? switches::kUnifiedGestureDetectorEnabled
+                         : switches::kUnifiedGestureDetectorDisabled);
 
     AuraTestBase::SetUp();
   }

ui/events/event_switches.cc

@@ -19,8 +19,18 @@ const char kTouchEventsAuto[] = "auto";
 const char kTouchEventsEnabled[] = "enabled";
 //   disabled: touch events are disabled.
 const char kTouchEventsDisabled[] = "disabled";
-// Use the unified gesture detector, instead of the aura gesture detector.
-const char kUseUnifiedGestureDetector[] = "use-unified-gesture-detector";
+
+// Enable the unified gesture detector, instead of the aura gesture detector.
+const char kUnifiedGestureDetector[] = "unified-gesture-detector";
+
+// The values the kUnifiedGestureDetector switch may have, as in
+// --unified-gesture-detector=disabled.
+//   auto: Same as disabled.
+const char kUnifiedGestureDetectorAuto[] = "auto";
+//   enabled: Use the unified gesture detector.
+const char kUnifiedGestureDetectorEnabled[] = "enabled";
+//   disabled: Use the aura gesture detector.
+const char kUnifiedGestureDetectorDisabled[] = "disabled";
 
 #if defined(OS_LINUX)
 // Tells chrome to interpret events from these devices as touch events. Only

ui/events/event_switches.h

@@ -15,7 +15,10 @@ EVENTS_BASE_EXPORT extern const char kTouchEvents[];
 EVENTS_BASE_EXPORT extern const char kTouchEventsAuto[];
 EVENTS_BASE_EXPORT extern const char kTouchEventsEnabled[];
 EVENTS_BASE_EXPORT extern const char kTouchEventsDisabled[];
-EVENTS_BASE_EXPORT extern const char kUseUnifiedGestureDetector[];
+EVENTS_BASE_EXPORT extern const char kUnifiedGestureDetector[];
+EVENTS_BASE_EXPORT extern const char kUnifiedGestureDetectorAuto[];
+EVENTS_BASE_EXPORT extern const char kUnifiedGestureDetectorEnabled[];
+EVENTS_BASE_EXPORT extern const char kUnifiedGestureDetectorDisabled[];
 
 #if defined(OS_LINUX)
 EVENTS_BASE_EXPORT extern const char kTouchDevices[];

ui/events/gestures/gesture_recognizer_impl.cc

@@ -68,9 +68,29 @@ GestureProviderAura* CreateGestureProvider(GestureProviderAuraClient* client) {
 ////////////////////////////////////////////////////////////////////////////////
 // GestureRecognizerImpl, public:
 
-GestureRecognizerImpl::GestureRecognizerImpl()
-    : use_unified_gesture_detector_(CommandLine::ForCurrentProcess()->HasSwitch(
-          switches::kUseUnifiedGestureDetector)) {
+GestureRecognizerImpl::GestureRecognizerImpl() {
+  // Default to not using the unified gesture detector.
+  const CommandLine& command_line = *CommandLine::ForCurrentProcess();
+  const std::string unified_gd_enabled_switch =
+      command_line.HasSwitch(switches::kUnifiedGestureDetector) ?
+      command_line.GetSwitchValueASCII(switches::kUnifiedGestureDetector) :
+      switches::kUnifiedGestureDetectorAuto;
+
+  const bool kUseUnifiedGestureDetectorByDefault = false;
+  if (unified_gd_enabled_switch.empty() ||
+      unified_gd_enabled_switch == switches::kUnifiedGestureDetectorEnabled) {
+    use_unified_gesture_detector_ = true;
+  } else if (unified_gd_enabled_switch ==
+                 switches::kUnifiedGestureDetectorDisabled) {
+    use_unified_gesture_detector_ = false;
+  } else if (unified_gd_enabled_switch ==
+             switches::kUnifiedGestureDetectorAuto) {
+    use_unified_gesture_detector_ = kUseUnifiedGestureDetectorByDefault;
+  } else {
+    LOG(ERROR) << "Invalid --unified-gesture-detector option: "
+               << unified_gd_enabled_switch;
+    use_unified_gesture_detector_ = false;
+  }
 }
 
 GestureRecognizerImpl::~GestureRecognizerImpl() {