merge mozilla-inbound to mozilla-central. r=merge a=merge

MozReview-Commit-ID: 6My6YCrpLe9

widget/cocoa/nsChildView.h

@@ -172,6 +172,11 @@ class WidgetRenderingContext;
 
   // Gestures support
   //
+  // mGestureState is used to detect when Cocoa has called both
+  // magnifyWithEvent and rotateWithEvent within the same
+  // beginGestureWithEvent and endGestureWithEvent sequence. We
+  // discard the spurious gesture event so as not to confuse Gecko.
+  //
   // mCumulativeMagnification keeps track of the total amount of
   // magnification peformed during a magnify gesture so that we can
   // send that value with the final MozMagnifyGesture event.
@@ -182,6 +187,7 @@ class WidgetRenderingContext;
   enum {
     eGestureState_None,
     eGestureState_StartGesture,
+    eGestureState_MagnifyGesture,
     eGestureState_RotateGesture
   } mGestureState;
   float mCumulativeMagnification;
@@ -247,6 +253,7 @@ class WidgetRenderingContext;
  */
 - (void)swipeWithEvent:(NSEvent *)anEvent;
 - (void)beginGestureWithEvent:(NSEvent *)anEvent;
+- (void)magnifyWithEvent:(NSEvent *)anEvent;
 - (void)smartMagnifyWithEvent:(NSEvent *)anEvent;
 - (void)rotateWithEvent:(NSEvent *)anEvent;
 - (void)endGestureWithEvent:(NSEvent *)anEvent;

widget/cocoa/nsChildView.mm

@@ -4200,6 +4200,77 @@ NSEvent* gLastDragMouseDownEvent = nil;
   NS_OBJC_END_TRY_ABORT_BLOCK;
 }
 
+// Pinch zoom gesture.
+- (void)magnifyWithEvent:(NSEvent *)anEvent
+{
+  NS_OBJC_BEGIN_TRY_ABORT_BLOCK;
+
+  if (!anEvent || !mGeckoChild ||
+      [self beginOrEndGestureForEventPhase:anEvent]) {
+    return;
+  }
+
+  nsAutoRetainCocoaObject kungFuDeathGrip(self);
+
+  float deltaZ = [anEvent deltaZ];
+
+  EventMessage msg;
+  switch (mGestureState) {
+  case eGestureState_StartGesture:
+    msg = eMagnifyGestureStart;
+    mGestureState = eGestureState_MagnifyGesture;
+    break;
+
+  case eGestureState_MagnifyGesture:
+    msg = eMagnifyGestureUpdate;
+    break;
+
+  case eGestureState_None:
+  case eGestureState_RotateGesture:
+  default:
+    return;
+  }
+
+  // This sends the pinch gesture value as a fake wheel event that has the
+  // control key pressed so that pages can implement custom pinch gesture
+  // handling. It may seem strange that this doesn't use a wheel event with
+  // the deltaZ property set, but this matches Chrome's behavior as described
+  // at https://code.google.com/p/chromium/issues/detail?id=289887
+  //
+  // The intent of the formula below is to produce numbers similar to Chrome's
+  // implementation of this feature. Chrome implements deltaY using the formula
+  // "-100 * log(1 + [event magnification])" which is unfortunately incorrect.
+  // All deltas for a single pinch gesture should sum to 0 if the start and end
+  // of a pinch gesture end up in the same place. This doesn't happen in Chrome
+  // because they followed Apple's misleading documentation, which implies that
+  // "1 + [event magnification]" is the scale factor. The scale factor is
+  // instead "pow(ratio, [event magnification])" so "[event magnification]" is
+  // already in log space.
+  //
+  // The multiplication by the backing scale factor below counteracts the
+  // division by the backing scale factor in WheelEvent.
+  WidgetWheelEvent geckoWheelEvent(true, EventMessage::eWheel, mGeckoChild);
+  [self convertCocoaMouseEvent:anEvent toGeckoEvent:&geckoWheelEvent];
+  double backingScale = mGeckoChild->BackingScaleFactor();
+  geckoWheelEvent.mDeltaY = -100.0 * [anEvent magnification] * backingScale;
+  geckoWheelEvent.mModifiers |= MODIFIER_CONTROL;
+  mGeckoChild->DispatchWindowEvent(geckoWheelEvent);
+
+  // If the fake wheel event wasn't stopped, then send a normal magnify event.
+  if (!geckoWheelEvent.mFlags.mDefaultPrevented) {
+    WidgetSimpleGestureEvent geckoEvent(true, msg, mGeckoChild);
+    geckoEvent.mDelta = deltaZ;
+    [self convertCocoaMouseEvent:anEvent toGeckoEvent:&geckoEvent];
+    mGeckoChild->DispatchWindowEvent(geckoEvent);
+
+    // Keep track of the cumulative magnification for the final "magnify" event.
+    mCumulativeMagnification += deltaZ;
+  }
+
+  NS_OBJC_END_TRY_ABORT_BLOCK;
+}
+
+// Smart zoom gesture, i.e. two-finger double tap on trackpads.
 - (void)smartMagnifyWithEvent:(NSEvent *)anEvent
 {
   NS_OBJC_BEGIN_TRY_ABORT_BLOCK;
@@ -4250,6 +4321,7 @@ NSEvent* gLastDragMouseDownEvent = nil;
     break;
 
   case eGestureState_None:
+  case eGestureState_MagnifyGesture:
   default:
     return;
   }
@@ -4332,6 +4404,18 @@ NSEvent* gLastDragMouseDownEvent = nil;
   nsAutoRetainCocoaObject kungFuDeathGrip(self);
 
   switch (mGestureState) {
+  case eGestureState_MagnifyGesture:
+    {
+      // Setup the "magnify" event.
+      WidgetSimpleGestureEvent geckoEvent(true, eMagnifyGesture, mGeckoChild);
+      geckoEvent.mDelta = mCumulativeMagnification;
+      [self convertCocoaMouseEvent:anEvent toGeckoEvent:&geckoEvent];
+
+      // Send the event.
+      mGeckoChild->DispatchWindowEvent(geckoEvent);
+    }
+    break;
+
   case eGestureState_RotateGesture:
     {
       // Setup the "rotate" event.