MacViews: Clip contents for non-rectangular windows.

ui/views/cocoa/bridged_content_view.mm

Index: ui/views/cocoa/bridged_content_view.mm
diff --git a/ui/views/cocoa/bridged_content_view.mm b/ui/views/cocoa/bridged_content_view.mm
index 6022a44723bf99d9873d04bd6dcbebdb7bc66697..d2b765b33cbfbaed4bf39c4eb17fda46730f0f18 100644
--- a/ui/views/cocoa/bridged_content_view.mm
+++ b/ui/views/cocoa/bridged_content_view.mm
@@ -191,6 +191,9 @@ gfx::Rect GetFirstRectForRangeHelper(const ui::TextInputClient* client,
 - (void)paste:(id)sender;
 - (void)selectAll:(id)sender;
 
+// Update windowMask_ as per the current view bounds.
+- (void)updateWindowMask;
+
 @end
 
 @implementation BridgedContentView
@@ -267,28 +270,12 @@ gfx::Rect GetFirstRectForRangeHelper(const ui::TextInputClient* client,
   }
 }
 
-- (void)updateWindowMask {
-  DCHECK(![self inLiveResize]);
-  DCHECK(base::mac::IsOSMavericksOrEarlier());
-  DCHECK(hostedView_);
-
-  views::Widget* widget = hostedView_->GetWidget();
-  if (!widget->non_client_view())
-    return;
-
-  const NSRect frameRect = [self bounds];
-  gfx::Path mask;
-  widget->non_client_view()->GetWindowMask(gfx::Size(frameRect.size), &mask);
-  if (mask.isEmpty())
-    return;
-
-  windowMask_.reset([gfx::CreateNSBezierPathFromSkPath(mask) retain]);
+- (void)onSizeChanged {
+  [self updateWindowMask];
+}
 
-  // Convert to AppKit coordinate system.
-  NSAffineTransform* flipTransform = [NSAffineTransform transform];
-  [flipTransform translateXBy:0.0 yBy:frameRect.size.height];
-  [flipTransform scaleXBy:1.0 yBy:-1.0];
-  [windowMask_ transformUsingAffineTransform:flipTransform];
+- (NSBezierPath*)windowMask {
+  return windowMask_.get();
 }
 
 // BridgedContentView private implementation.
@@ -379,6 +366,28 @@ gfx::Rect GetFirstRectForRangeHelper(const ui::TextInputClient* client,
           eventFlags:ui::EF_CONTROL_DOWN];
 }
 
+- (void)updateWindowMask {
+  DCHECK(hostedView_);
+
+  views::Widget* widget = hostedView_->GetWidget();
+  if (!widget->non_client_view())
+    return;
+
+  const NSRect frameRect = [self bounds];
+  gfx::Path mask;
+  widget->non_client_view()->GetWindowMask(gfx::Size(frameRect.size), &mask);
+  if (mask.isEmpty())
+    return;
+
+  windowMask_.reset([gfx::CreateNSBezierPathFromSkPath(mask) retain]);
+
+  // Convert to AppKit coordinate system.
+  NSAffineTransform* flipTransform = [NSAffineTransform transform];
+  [flipTransform translateXBy:0.0 yBy:frameRect.size.height];
+  [flipTransform scaleXBy:1.0 yBy:-1.0];
+  [windowMask_ transformUsingAffineTransform:flipTransform];
+}
+
 // BaseView implementation.
 
 // Don't use tracking areas from BaseView. BridgedContentView's tracks
@@ -435,13 +444,11 @@ gfx::Rect GetFirstRectForRangeHelper(const ui::TextInputClient* client,
 - (void)viewDidEndLiveResize {
   [super viewDidEndLiveResize];
 
-  // We prevent updating the window mask and clipping the border around the
-  // view, during a live resize. Hence update the window mask and redraw the
-  // view after resize has completed.
-  if (base::mac::IsOSMavericksOrEarlier()) {
-    [self updateWindowMask];
+  // During a live resize, we prevent clipping the border around the view, which
+  // is required to generate drop shadows on OSX 10.9. Hence redraw the view
+  // after resize has completed.
+  if (base::mac::IsOSMavericksOrEarlier())
     [self setNeedsDisplay:YES];
-  }
 }
 
 - (void)drawRect:(NSRect)dirtyRect {
@@ -464,8 +471,8 @@ gfx::Rect GetFirstRectForRangeHelper(const ui::TextInputClient* client,
   // boundary with clearColor and tell Cococa to regenerate drop shadow. See
   // crbug.com/543671.
   if (windowMask_ && ![self inLiveResize] &&
-      !IsRectInsidePath(dirtyRect, windowMask_)) {
-    DCHECK(base::mac::IsOSMavericksOrEarlier());
+      !IsRectInsidePath(dirtyRect, windowMask_) &&
+      base::mac::IsOSMavericksOrEarlier()) {
     gfx::ScopedNSGraphicsContextSaveGState state;
 
     // The outer rectangular path corresponding to the window.