[Android] Perform eager gesture recognition on MotionEvents

content/browser/android/content_view_core_impl.cc

Index: content/browser/android/content_view_core_impl.cc
diff --git a/content/browser/android/content_view_core_impl.cc b/content/browser/android/content_view_core_impl.cc
index 182c0a6f336ca2071a3303065f41072bb9fa2e4b..efe44b462b7d3b250561f009f30973be249720c7 100644
--- a/content/browser/android/content_view_core_impl.cc
+++ b/content/browser/android/content_view_core_impl.cc
@@ -33,6 +33,7 @@
 #include "content/browser/renderer_host/render_widget_host_view_android.h"
 #include "content/browser/ssl/ssl_host_state.h"
 #include "content/browser/web_contents/web_contents_view_android.h"
+#include "content/common/input/web_input_event_traits.h"
 #include "content/common/input_messages.h"
 #include "content/common/view_messages.h"
 #include "content/public/browser/browser_accessibility_state.h"
@@ -110,6 +111,94 @@ ScopedJavaLocalRef<jobject> CreateJavaRect(
                                       static_cast<int>(rect.bottom())));
 }
 
+bool PossiblyTriggeredByTimeout(const WebGestureEvent& event) {
+  switch (event.type) {
+    case WebInputEvent::GestureShowPress:
+    case WebInputEvent::GestureLongPress:
+      return true;
+    // On Android, a GestureTap may be sent after a certain timeout window
+    // if there is no GestureDoubleTap follow-up.
+    case WebInputEvent::GestureTap:
+      return true;
+    // On Android, a GestureTapCancel may be triggered by the loss of window
+    //  focus (e.g., following a GestureLongPress).
+    case WebInputEvent::GestureTapCancel:
+      return true;
+    default:
+      break;
+  }
+  return false;
+}
+
+GestureEventPacket::GestureSource
+ToGestureSource(const WebGestureEvent& event) {
+  return PossiblyTriggeredByTimeout(event) ? GestureEventPacket::TOUCH_TIMEOUT
+                                           : GestureEventPacket::SYNTHETIC;
+}
+
+int ToContentViewGestureHandlerType(WebInputEvent::Type type) {
+  // These values should match exactly those in ContentViewGestureHandler.
+  enum ContentViewGestureHandlerType {
+    GESTURE_SHOW_PRESS = 0,
+    GESTURE_DOUBLE_TAP = 1,
+    GESTURE_SINGLE_TAP_UP = 2,
+    GESTURE_SINGLE_TAP_CONFIRMED = 3,
+    GESTURE_SINGLE_TAP_UNCONFIRMED = 4,
+    GESTURE_LONG_PRESS = 5,
+    GESTURE_SCROLL_START = 6,
+    GESTURE_SCROLL_BY = 7,
+    GESTURE_SCROLL_END = 8,
+    GESTURE_FLING_START = 9,
+    GESTURE_FLING_CANCEL = 10,
+    GESTURE_PINCH_BEGIN = 11,
+    GESTURE_PINCH_BY = 12,
+    GESTURE_PINCH_END = 13,
+    GESTURE_TAP_CANCEL = 14,
+    GESTURE_LONG_TAP = 15,
+    GESTURE_TAP_DOWN = 16
+  };
+  switch (type) {
+    case WebInputEvent::GestureScrollBegin:
+      return GESTURE_SCROLL_START;
+    case WebInputEvent::GestureScrollEnd:
+      return GESTURE_SCROLL_END;
+    case WebInputEvent::GestureScrollUpdate:
+      return GESTURE_SCROLL_BY;
+    case WebInputEvent::GestureFlingStart:
+      return GESTURE_FLING_START;
+    case WebInputEvent::GestureFlingCancel:
+      return GESTURE_FLING_CANCEL;
+    case WebInputEvent::GestureShowPress:
+      return GESTURE_SHOW_PRESS;
+    case WebInputEvent::GestureTap:
+      return GESTURE_SINGLE_TAP_CONFIRMED;
+    case WebInputEvent::GestureTapUnconfirmed:
+      return GESTURE_SINGLE_TAP_UNCONFIRMED;
+    case WebInputEvent::GestureTapDown:
+      return GESTURE_TAP_DOWN;
+    case WebInputEvent::GestureTapCancel:
+      return GESTURE_TAP_CANCEL;
+    case WebInputEvent::GestureDoubleTap:
+      return GESTURE_DOUBLE_TAP;
+    case WebInputEvent::GestureLongPress:
+      return GESTURE_LONG_PRESS;
+    case WebInputEvent::GestureLongTap:
+      return GESTURE_LONG_TAP;
+    case WebInputEvent::GesturePinchBegin:
+      return GESTURE_PINCH_BEGIN;
+    case WebInputEvent::GesturePinchEnd:
+      return GESTURE_PINCH_END;
+    case WebInputEvent::GesturePinchUpdate:
+      return GESTURE_PINCH_BY;
+    case WebInputEvent::GestureTwoFingerTap:
+    case WebInputEvent::GestureScrollUpdateWithoutPropagation:
+    default:
+      NOTREACHED() << "Invalid source gesture type: "
+                   << WebInputEventTraits::GetName(type);
+      return -1;
+  };
+}
+
 }  // namespace
 
 // Enables a callback when the underlying WebContents is destroyed, to enable
@@ -176,7 +265,9 @@ ContentViewCoreImpl::ContentViewCoreImpl(JNIEnv* env,
       view_android_(view_android),
       window_android_(window_android),
       device_orientation_(0),
-      geolocation_needs_pause_(false) {
+      geolocation_needs_pause_(false),
+      gesture_event_queue_(this),
+      handling_touch_event_(false) {
   CHECK(web_contents) <<
       "A ContentViewCoreImpl should be created with a valid WebContents.";
 
@@ -302,6 +393,23 @@ void ContentViewCoreImpl::RenderViewReady() {
     SendOrientationChangeEventInternal();
 }
 
+void ContentViewCoreImpl::ForwardGestureEvent(
+    const blink::WebGestureEvent& event) {
+  JNIEnv* env = AttachCurrentThread();
+  ScopedJavaLocalRef<jobject> j_obj = java_ref_.get(env);
+  if (j_obj.is_null())
+    return;
+
+  if (!Java_ContentViewCore_onForwardingGestureEvent(
+          env, j_obj.obj(),
+          ToContentViewGestureHandlerType(event.type), event.x, event.y))
+    return;
+
+  RenderWidgetHostViewAndroid* rwhv = GetRenderWidgetHostViewAndroid();
+  if (rwhv)
+    rwhv->SendGestureEvent(event);
+}
+
 RenderWidgetHostViewAndroid*
     ContentViewCoreImpl::GetRenderWidgetHostViewAndroid() {
   RenderWidgetHostView* rwhv = NULL;
@@ -495,21 +603,18 @@ void ContentViewCoreImpl::ShowSelectPopupMenu(
 }
 
 void ContentViewCoreImpl::ConfirmTouchEvent(InputEventAckState ack_result) {
-  JNIEnv* env = AttachCurrentThread();
-  ScopedJavaLocalRef<jobject> j_obj = java_ref_.get(env);
-  if (j_obj.is_null())
-    return;
-  Java_ContentViewCore_confirmTouchEvent(env, j_obj.obj(),
-                                         static_cast<jint>(ack_result));
+  gesture_event_queue_.OnTouchEventAck(ack_result);
 }
 
-void ContentViewCoreImpl::OnFlingStartEventAck(InputEventAckState ack_result) {
+void ContentViewCoreImpl::OnUnhandledFlingStartEventAck(bool had_consumer,
+                                                        float vx,
+                                                        float vy) {
   JNIEnv* env = AttachCurrentThread();
   ScopedJavaLocalRef<jobject> j_obj = java_ref_.get(env);
   if (j_obj.is_null())
     return;
-  Java_ContentViewCore_onFlingStartEventAck(env, j_obj.obj(),
-                                            static_cast<jint>(ack_result));
+  Java_ContentViewCore_onUnhandledFlingStartEventAck(env, j_obj.obj(),
+                                                     had_consumer, vx, vy);
 }
 
 void ContentViewCoreImpl::OnScrollBeginEventAck() {
@@ -536,16 +641,6 @@ void ContentViewCoreImpl::OnScrollEndEventAck() {
   Java_ContentViewCore_onScrollEndEventAck(env, j_obj.obj());
 }
 
-void ContentViewCoreImpl::HasTouchEventHandlers(bool need_touch_events) {
-  JNIEnv* env = AttachCurrentThread();
-  ScopedJavaLocalRef<jobject> j_obj = java_ref_.get(env);
-  if (j_obj.is_null())
-    return;
-  Java_ContentViewCore_hasTouchEventHandlers(env,
-                                             j_obj.obj(),
-                                             need_touch_events);
-}
-
 bool ContentViewCoreImpl::HasFocus() {
   JNIEnv* env = AttachCurrentThread();
   ScopedJavaLocalRef<jobject> obj = java_ref_.get(env);
@@ -919,21 +1014,32 @@ void ContentViewCoreImpl::SendOrientationChangeEvent(JNIEnv* env,
   }
 }
 
-jboolean ContentViewCoreImpl::SendTouchEvent(JNIEnv* env,
-                                             jobject obj,
-                                             jlong time_ms,
-                                             jint type,
-                                             jobjectArray pts) {
+void ContentViewCoreImpl::OnTouchEventHandlingBegin(JNIEnv* env,
+                                                    jobject obj,
+                                                    jlong time_ms,
+                                                    jint type,
+                                                    jobjectArray pts) {
+  DCHECK(!handling_touch_event_);
+  handling_touch_event_ = true;
+
+  blink::WebTouchEvent event;
+  TouchPoint::BuildWebTouchEvent(env, type, time_ms, GetDpiScale(), pts, event);
+  pending_touch_event_ = event;
+
+  pending_gesture_packet_ = GestureEventPacket::FromTouch(event);
+}
+
+void ContentViewCoreImpl::OnTouchEventHandlingEnd(JNIEnv* env, jobject obj) {
+  DCHECK(handling_touch_event_);
+  handling_touch_event_ = false;
+
   RenderWidgetHostViewAndroid* rwhv = GetRenderWidgetHostViewAndroid();
-  if (rwhv) {
-    using blink::WebTouchEvent;
-    blink::WebTouchEvent event;
-    TouchPoint::BuildWebTouchEvent(env, type, time_ms, GetDpiScale(), pts,
-        event);
-    rwhv->SendTouchEvent(event);
-    return true;
-  }
-  return false;
+  if (!rwhv)
+    return;
+
+  // Note: Order is important here, as the touch may be ack'ed synchronously
+  gesture_event_queue_.OnGestureEventPacket(pending_gesture_packet_);
+  rwhv->SendTouchEvent(pending_touch_event_);
 }
 
 float ContentViewCoreImpl::GetTouchPaddingDip() {
@@ -1003,9 +1109,18 @@ WebGestureEvent ContentViewCoreImpl::MakeGestureEvent(
 
 void ContentViewCoreImpl::SendGestureEvent(
     const blink::WebGestureEvent& event) {
-  RenderWidgetHostViewAndroid* rwhv = GetRenderWidgetHostViewAndroid();
-  if (rwhv)
-    rwhv->SendGestureEvent(event);
+  if (handling_touch_event_) {
+    pending_gesture_packet_.Push(event);
+    return;
+  }
+  gesture_event_queue_.OnGestureEventPacket(
+      GestureEventPacket::FromGesture(ToGestureSource(event), event));
+}
+
+void ContentViewCoreImpl::SendSyntheticGestureEvent(
+    const blink::WebGestureEvent& event) {
+  gesture_event_queue_.OnGestureEventPacket(
+      GestureEventPacket::FromGesture(GestureEventPacket::SYNTHETIC, event));
 }
 
 void ContentViewCoreImpl::ScrollBegin(JNIEnv* env,
@@ -1065,12 +1180,14 @@ void ContentViewCoreImpl::SingleTap(JNIEnv* env, jobject obj, jlong time_ms,
       WebInputEvent::GestureTap, time_ms, x, y);
 
   event.data.tap.tapCount = 1;
-  if (!disambiguation_popup_tap) {
-    const float touch_padding_dip = GetTouchPaddingDip();
-    event.data.tap.width = touch_padding_dip;
-    event.data.tap.height = touch_padding_dip;
+  if (disambiguation_popup_tap) {
+    SendSyntheticGestureEvent(event);
+    return;
   }
 
+  const float touch_padding_dip = GetTouchPaddingDip();
+  event.data.tap.width = touch_padding_dip;
+  event.data.tap.height = touch_padding_dip;
   SendGestureEvent(event);
 }
 
@@ -1089,9 +1206,9 @@ void ContentViewCoreImpl::SingleTapUnconfirmed(JNIEnv* env, jobject obj,
   SendGestureEvent(event);
 }
 
-void ContentViewCoreImpl::ShowPressState(JNIEnv* env, jobject obj,
-                                         jlong time_ms,
-                                         jfloat x, jfloat y) {
+void ContentViewCoreImpl::ShowPress(JNIEnv* env, jobject obj,
+                                    jlong time_ms,
+                                    jfloat x, jfloat y) {
   WebGestureEvent event = MakeGestureEvent(
       WebInputEvent::GestureShowPress, time_ms, x, y);
   SendGestureEvent(event);
@@ -1128,12 +1245,14 @@ void ContentViewCoreImpl::LongPress(JNIEnv* env, jobject obj, jlong time_ms,
   WebGestureEvent event = MakeGestureEvent(
       WebInputEvent::GestureLongPress, time_ms, x, y);
 
-  if (!disambiguation_popup_tap) {
-    const float touch_padding_dip = GetTouchPaddingDip();
-    event.data.longPress.width = touch_padding_dip;
-    event.data.longPress.height = touch_padding_dip;
+  if (disambiguation_popup_tap) {
+    SendSyntheticGestureEvent(event);
+    return;
   }
 
+  const float touch_padding_dip = GetTouchPaddingDip();
+  event.data.longPress.width = touch_padding_dip;
+  event.data.longPress.height = touch_padding_dip;
   SendGestureEvent(event);
 }
 
@@ -1143,12 +1262,14 @@ void ContentViewCoreImpl::LongTap(JNIEnv* env, jobject obj, jlong time_ms,
   WebGestureEvent event = MakeGestureEvent(
       WebInputEvent::GestureLongTap, time_ms, x, y);
 
-  if (!disambiguation_popup_tap) {
-    const float touch_padding_dip = GetTouchPaddingDip();
-    event.data.longPress.width = touch_padding_dip;
-    event.data.longPress.height = touch_padding_dip;
+  if (disambiguation_popup_tap) {
+    SendSyntheticGestureEvent(event);
+    return;
   }
 
+  const float touch_padding_dip = GetTouchPaddingDip();
+  event.data.longPress.width = touch_padding_dip;
+  event.data.longPress.height = touch_padding_dip;
   SendGestureEvent(event);
 }