mac: Remove uses of a CoreGraphics private API that causes WindowServer crashes.

ui/base/cocoa/constrained_window/constrained_window_animation.mm

Index: ui/base/cocoa/constrained_window/constrained_window_animation.mm
diff --git a/ui/base/cocoa/constrained_window/constrained_window_animation.mm b/ui/base/cocoa/constrained_window/constrained_window_animation.mm
index 3618a1b97825fc36365861ab3d3928d170cb3f2b..b691536d0d0e2fe9118fd03c233ee2ffb792617b 100644
--- a/ui/base/cocoa/constrained_window/constrained_window_animation.mm
+++ b/ui/base/cocoa/constrained_window/constrained_window_animation.mm
@@ -20,18 +20,12 @@
 // - Perspective and shear transformations get clipped if they are bigger
 //   than the window size. This does not seem to apply to scale transformations.
 
+// Use of private APIs is dangerous, and is known to cause WindowServer crashes.
+// https://bugs.chromium.org/p/chromium/issues/detail?id=515627
+
 // Length of the animation in seconds.
 const NSTimeInterval kAnimationDuration = 0.18;
 
-// The number of pixels above the final destination to animate from.
-const CGFloat kShowHideVerticalOffset = 20;
-
-// Scale the window by this factor when animating.
-const CGFloat kShowHideScaleFactor = 0.99;
-
-// Size of the perspective effect as a factor of the window width.
-const CGFloat kShowHidePerspectiveFactor = 0.04;
-
 // Forward declare private CoreGraphics APIs used to transform windows.
 extern "C" {
 
@@ -54,11 +48,6 @@ CGSConnection _CGSDefaultConnection();
 CGError CGSSetWindowTransform(const CGSConnection cid,

[tapted, 2016/03/14 00:03:22]

You said CGSSetWindowWarp caused the crashes, but the logs had
 > ERROR: CGSSetWindowTransformAtPlacement() returned 268435459

Is that weird/something to worry about?

(Did you try out the `pulse` on the VM with the extension install dialog open,
by mashing clicks on the webcontents in the background?)

                               const CGSWindow wid,
                               CGAffineTransform transform);
-CGError CGSSetWindowWarp(const CGSConnection cid,
-                         const CGSWindow wid,
-                         int32_t w,
-                         int32_t h,
-                         CGPointWarp* mesh);
 CGError CGSSetWindowAlpha(const CGSConnection cid,
                           const CGSWindow wid,
                           float32 alpha);
@@ -119,74 +108,11 @@ void SetWindowScale(NSWindow* window, float scale) {
   CGSSetWindowTransform(cid, [window windowNumber], transform);
 }
 
-// Unsets any window warp that may have been previously applied.
-// Window warp prevents other effects such as CGSSetWindowTransform from
-// being applied.
-void ClearWindowWarp(NSWindow* window) {
-  CGSConnection cid = _CGSDefaultConnection();
-  CGSSetWindowWarp(cid, [window windowNumber], 0, 0, NULL);
-}
-
-// Applies various transformations using a warp effect. The window is
-// translated vertically by |y_offset|. The window is scaled by |scale| and
-// translated so that the it remains centered relative to its original position.
-// Finally, perspective is effect is applied by shrinking the top of the window.
-void SetWindowWarp(NSWindow* window,
-                   float y_offset,
-                   float scale,
-                   float perspective_offset) {
-  NSRect win_rect = [window frame];
-  win_rect.origin = NSZeroPoint;
-  NSRect screen_rect = win_rect;
-  screen_rect.origin = GetCGSWindowScreenOrigin(window);
-
-  // Apply a vertical translate.
-  screen_rect.origin.y -= y_offset;
-
-  // Apply a scale and translate to keep the window centered.
-  screen_rect.origin.x += (NSWidth(win_rect) - NSWidth(screen_rect)) / 2.0;
-  screen_rect.origin.y += (NSHeight(win_rect) - NSHeight(screen_rect)) / 2.0;
-
-  // A 2 x 2 mesh that maps each corner of the window to a location in screen
-  // coordinates. Note that the origin of the coordinate system is top, left.
-  CGPointWarp mesh[2][2] = {
-      {{
-        // Top left.
-        {NSMinX(win_rect), NSMinY(win_rect)},
-        {NSMinX(screen_rect) + perspective_offset, NSMinY(screen_rect)},
-       },
-       {
-        // Top right.
-        {NSMaxX(win_rect), NSMinY(win_rect)},
-        {NSMaxX(screen_rect) - perspective_offset, NSMinY(screen_rect)}, }},
-      {{
-        // Bottom left.
-        {NSMinX(win_rect), NSMaxY(win_rect)},
-        {NSMinX(screen_rect), NSMaxY(screen_rect)},
-       },
-       {
-        // Bottom right.
-        {NSMaxX(win_rect), NSMaxY(win_rect)},
-        {NSMaxX(screen_rect), NSMaxY(screen_rect)}, }},
-  };
-
-  CGSConnection cid = _CGSDefaultConnection();
-  CGSSetWindowWarp(cid, [window windowNumber], 2, 2, &(mesh[0][0]));
-}
-
 // Sets the various effects that are a part of the Show/Hide animation.
 // Value is a number between 0 and 1 where 0 means the window is completely
 // hidden and 1 means the window is fully visible.
 void UpdateWindowShowHideAnimationState(NSWindow* window, CGFloat value) {
-  CGFloat inverse_value = 1.0 - value;
-
   SetWindowAlpha(window, value);
-  CGFloat y_offset = kShowHideVerticalOffset * inverse_value;
-  CGFloat scale = 1.0 - (1.0 - kShowHideScaleFactor) * inverse_value;
-  CGFloat perspective_offset =
-      ([window frame].size.width * kShowHidePerspectiveFactor) * inverse_value;
-
-  SetWindowWarp(window, y_offset, scale, perspective_offset);
 }
 
 }  // namespace
@@ -255,7 +181,6 @@ void UpdateWindowShowHideAnimationState(NSWindow* window, CGFloat value) {
 
 - (void)setWindowStateForEnd {
   SetWindowAlpha(window_, 1.0);
-  ClearWindowWarp(window_);
 }
 
 @end
@@ -268,7 +193,6 @@ void UpdateWindowShowHideAnimationState(NSWindow* window, CGFloat value) {
 
 - (void)setWindowStateForEnd {
   SetWindowAlpha(window_, 0.0);
-  ClearWindowWarp(window_);
 }
 
 @end