Support detaching/attaching panels via inter-strip drags.

chrome/browser/ui/panels/panel_titlebar_view_cocoa.mm

Index: chrome/browser/ui/panels/panel_titlebar_view_cocoa.mm
diff --git a/chrome/browser/ui/panels/panel_titlebar_view_cocoa.mm b/chrome/browser/ui/panels/panel_titlebar_view_cocoa.mm
index f637494ac95ed9f19e0ef0f0df412e1817f0b593..f2218c4132e1d11004845bff95da53d0703ed772 100644
--- a/chrome/browser/ui/panels/panel_titlebar_view_cocoa.mm
+++ b/chrome/browser/ui/panels/panel_titlebar_view_cocoa.mm
@@ -392,7 +392,7 @@ static NSEvent* MakeMouseEvent(NSEventType type,
 - (void)mouseDown:(NSEvent*)event {
   if ([controller_ isDraggable]) {
     dragState_ = PANEL_DRAG_CAN_START;
-    dragStartLocation_ = [event locationInWindow];
+    dragStartLocation_ = [NSEvent mouseLocation];
   }
 }
 
@@ -406,7 +406,7 @@ static NSEvent* MakeMouseEvent(NSEventType type,
 - (BOOL)exceedsDragThreshold:(NSPoint)mouseLocation {
   float deltaX = dragStartLocation_.x - mouseLocation.x;
   float deltaY = dragStartLocation_.y - mouseLocation.y;
-  return deltaX > kDragThreshold || deltaY > kDragThreshold;
+  return fabs(deltaX) > kDragThreshold || fabs(deltaY) > kDragThreshold;
 }
 
 - (void)mouseDragged:(NSEvent*)event {
@@ -432,12 +432,12 @@ static NSEvent* MakeMouseEvent(NSEventType type,
     switch ([event type]) {
       case NSLeftMouseDragged:
         if (dragState_ == PANEL_DRAG_CAN_START) {
-          if (![self exceedsDragThreshold:[event locationInWindow]])
+          if (![self exceedsDragThreshold:[NSEvent mouseLocation]])
             return;  // Don't start real drag yet.
-          [self startDrag];
+          [self startDrag:dragStartLocation_];
         }
-        [self dragWithDeltaX:[event deltaX]
-                      deltaY:[event deltaY]];
+        if (dragState_ == PANEL_DRAG_IN_PROGRESS)
+          [self drag:[NSEvent mouseLocation]];
         break;
 
       case NSKeyUp:
@@ -468,10 +468,10 @@ static NSEvent* MakeMouseEvent(NSEventType type,
   }
 }
 
-- (void)startDrag {
+- (void)startDrag:(NSPoint)mouseLocation {
   DCHECK(dragState_ == PANEL_DRAG_CAN_START);
   dragState_ = PANEL_DRAG_IN_PROGRESS;
-  [controller_ startDrag];
+  [controller_ startDrag:mouseLocation];
 }
 
 - (void)endDrag:(BOOL)cancelled {
@@ -480,12 +480,10 @@ static NSEvent* MakeMouseEvent(NSEventType type,
   dragState_ = PANEL_DRAG_SUPPRESSED;
 }
 
-- (void)dragWithDeltaX:(int)deltaX
-                deltaY:(int)deltaY {
+- (void)drag:(NSPoint)mouseLocation {
   if (dragState_ != PANEL_DRAG_IN_PROGRESS)
     return;
-  [controller_ dragWithDeltaX:deltaX
-                       deltaY:deltaY];
+  [controller_ drag:mouseLocation];
 }
 
 - (void)drawAttention {
@@ -569,8 +567,9 @@ static NSEvent* MakeMouseEvent(NSEventType type,
   [[closeButton_ cell] performClick:closeButton_];
 }
 
-- (void)pressLeftMouseButtonTitlebar {
-  NSEvent* event = MakeMouseEvent(NSLeftMouseDown, NSZeroPoint, 0);
+- (void)pressLeftMouseButtonTitlebar:(NSPoint)mouseLocation {
+  NSEvent* event = MakeMouseEvent(NSLeftMouseDown,
+      [self convertPoint:mouseLocation fromView:nil], 0);
   [self mouseDown:event];
 }
 
@@ -579,12 +578,10 @@ static NSEvent* MakeMouseEvent(NSEventType type,
   [self mouseUp:event];
 }
 
-- (void)dragTitlebarDeltaX:(double)delta_x
-                    deltaY:(double)delta_y {
+- (void)dragTitlebar:(NSPoint)mouseLocation {
   if (dragState_ == PANEL_DRAG_CAN_START)
-    [self startDrag];
-  [self dragWithDeltaX:delta_x
-                deltaY:delta_y];
+    [self startDrag:dragStartLocation_];
+  [self drag:mouseLocation];
 }
 
 - (void)cancelDragTitlebar {