Fix flipped views on Mac

Setting a layer-hosting NSView's CALayer's geometry flipping has a lot
of unexpected side-effects, and is proving unsafe, especially if that
NSView will have sub-views.

Add a level of indirection where the hosted layer is not flipped, but it
has a sub-layer that is flipped, off of which the layers for composited
content are attached.

BUG=392952

Review URL: https://codereview.chromium.org/392143002

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@283862 0039d316-1c4b-4281-b951-d872f2087c98

content/browser/compositor/OWNERS

@@ -2,3 +2,4 @@ piman@chromium.org
 danakj@chromium.org
 sievers@chromium.org
 jbauman@chromium.org
+ccameron@chromium.org

content/browser/compositor/browser_compositor_view_private_mac.h

@@ -17,10 +17,19 @@ class BrowserCompositorViewCocoaHelper;
 @interface BrowserCompositorViewCocoa : NSView {
   scoped_ptr<ui::Compositor> compositor_;
 
-  base::scoped_nsobject<CALayer> background_layer_;
+  // A flipped layer, which acts as the parent of the compositing and software
+  // layers. This layer is flipped so that the we don't need to recompute the
+  // origin for sub-layers when their position changes (this is impossible when
+  // using remote layers, as their size change cannot be synchronized with the
+  // window). This indirection is needed because flipping hosted layers (like
+  // |background_layer_| of RenderWidgetHostViewCocoa) leads to unpredictable
+  // behavior.
+  base::scoped_nsobject<CALayer> flipped_layer_;
+
   base::scoped_nsobject<CompositingIOSurfaceLayer> accelerated_layer_;
   int accelerated_layer_output_surface_id_;
   std::vector<ui::LatencyInfo> accelerated_latency_info_;
+
   base::scoped_nsobject<SoftwareLayer> software_layer_;
 
   content::BrowserCompositorViewMacClient* client_;

content/browser/compositor/browser_compositor_view_private_mac.mm

@@ -27,11 +27,14 @@
     // Disable the fade-in animation as the layer and view are added.
     ScopedCAActionDisabler disabler;
 
-    // Make this view host a transparent layer.
-    background_layer_.reset([[CALayer alloc] init]);
-    [background_layer_ setContentsGravity:kCAGravityTopLeft];
-    [self setLayer:background_layer_];
-    [self setWantsLayer:YES];
+    // Add a flipped transparent layer as a child, so that we don't need to
+    // fiddle with the position of sub-layers -- they will always be at the
+    // origin.
+    flipped_layer_.reset([[CALayer alloc] init]);
+    [flipped_layer_ setGeometryFlipped:YES];
+    [flipped_layer_ setAnchorPoint:CGPointMake(0, 0)];
+    [flipped_layer_
+        setAutoresizingMask:kCALayerWidthSizable|kCALayerHeightSizable];
 
     compositor_.reset(new ui::Compositor(self, content::GetContextFactory()));
   }
@@ -41,9 +44,9 @@
 - (void)setClient:(content::BrowserCompositorViewMacClient*)client {
   // Disable the fade-out as layers are removed.
   ScopedCAActionDisabler disabler;
-  [self removeFromSuperview];
 
   // Reset all state.
+  [flipped_layer_ removeFromSuperlayer];
   [accelerated_layer_ removeFromSuperlayer];
   [accelerated_layer_ resetClient];
   accelerated_layer_.reset();
@@ -56,7 +59,10 @@
   if (client_) {
     DCHECK(compositor_);
     compositor_->SetRootLayer(client_->BrowserCompositorRootLayer());
-    [client_->BrowserCompositorSuperview() addSubview:self];
+    CALayer* background_layer = [client_->BrowserCompositorSuperview() layer];
+    DCHECK(background_layer);
+    [flipped_layer_ setBounds:[background_layer bounds]];
+    [background_layer addSublayer:flipped_layer_];
   } else {
     compositor_->SetRootLayer(NULL);
   }
@@ -111,7 +117,7 @@
         initWithIOSurface:iosurface
           withScaleFactor:scale_factor
                withClient:helper_.get()]);
-    [[self layer] addSublayer:accelerated_layer_];
+    [flipped_layer_ addSublayer:accelerated_layer_];
   }
 
   {
@@ -163,7 +169,7 @@
     // Disable the fade-in animation as the layer is added.
     ScopedCAActionDisabler disabler;
     software_layer_.reset([[SoftwareLayer alloc] init]);
-    [[self layer] addSublayer:software_layer_];
+    [flipped_layer_ addSublayer:software_layer_];
   }
 
   SkImageInfo info;

content/browser/renderer_host/render_widget_host_view_mac.h

@@ -411,9 +411,16 @@ class CONTENT_EXPORT RenderWidgetHostViewMac
   bool can_compose_inline_;
 
   // The background CoreAnimation layer which is hosted by |cocoa_view_|.
-  // The compositing or software layers will be added as sublayers to this.
   base::scoped_nsobject<CALayer> background_layer_;
 
+  // A flipped layer, which acts as the parent of the compositing and software
+  // layers. This layer is flipped so that the we don't need to recompute the
+  // origin for sub-layers when their position changes (this is impossible when
+  // using remote layers, as their size change cannot be synchronized with the
+  // window). This indirection is needed because flipping hosted layers (like
+  // |background_layer_|) leads to unpredictable behavior.
+  base::scoped_nsobject<CALayer> flipped_layer_;
+
   // The CoreAnimation layer hosted by the GPU process.
   base::scoped_nsobject<CALayerHost> remote_layer_host_;
 

content/browser/renderer_host/render_widget_host_view_mac.mm

@@ -513,14 +513,25 @@ RenderWidgetHostViewMac::RenderWidgetHostViewMac(RenderWidgetHost* widget)
   cocoa_view_ = [[[RenderWidgetHostViewCocoa alloc]
                   initWithRenderWidgetHostViewMac:this] autorelease];
 
+  // Make this view host a solid white layer when there is no content ready to
+  // draw.
   background_layer_.reset([[CALayer alloc] init]);
   [background_layer_
       setBackgroundColor:CGColorGetConstantColor(kCGColorWhite)];
-  [background_layer_ setGeometryFlipped:YES];
-  [background_layer_ setContentsGravity:kCAGravityTopLeft];
   [cocoa_view_ setLayer:background_layer_];
   [cocoa_view_ setWantsLayer:YES];
 
+  if (!IsDelegatedRendererEnabled()) {
+    // Add a flipped transparent layer as a child, so that we don't need to
+    // fiddle with the position of sub-layers -- they will always be at the
+    // origin.
+    flipped_layer_.reset([[CALayer alloc] init]);
+    [flipped_layer_ setGeometryFlipped:YES];
+    [flipped_layer_
+        setAutoresizingMask:kCALayerWidthSizable|kCALayerHeightSizable];
+    [background_layer_ addSublayer:flipped_layer_];
+  }
+
   if (IsDelegatedRendererEnabled()) {
     root_layer_.reset(new ui::Layer(ui::LAYER_TEXTURED));
     delegated_frame_host_.reset(new DelegatedFrameHost(this));
@@ -653,7 +664,7 @@ void RenderWidgetHostViewMac::EnsureSoftwareLayer() {
 
   // Disable the fade-in animation as the layer is added.
   ScopedCAActionDisabler disabler;
-  [background_layer_ addSublayer:software_layer_];
+  [flipped_layer_ addSublayer:software_layer_];
 }
 
 void RenderWidgetHostViewMac::DestroySoftwareLayer() {
@@ -681,7 +692,7 @@ void RenderWidgetHostViewMac::EnsureCompositedIOSurfaceLayer() {
 
   // Disable the fade-in animation as the layer is added.
   ScopedCAActionDisabler disabler;
-  [background_layer_ addSublayer:compositing_iosurface_layer_];
+  [flipped_layer_ addSublayer:compositing_iosurface_layer_];
 }
 
 void RenderWidgetHostViewMac::DestroyCompositedIOSurfaceLayer(
@@ -1754,7 +1765,7 @@ void RenderWidgetHostViewMac::AcceleratedSurfaceBuffersSwapped(
         [remote_layer_host_ setContextId:context_id];
         [remote_layer_host_
             setAutoresizingMask:kCALayerMaxXMargin|kCALayerMaxYMargin];
-        [background_layer_ addSublayer:remote_layer_host_];
+        [flipped_layer_ addSublayer:remote_layer_host_];
       }
 
       // Ack the frame immediately. Any GPU back pressure will be applied by
@@ -2192,7 +2203,7 @@ void RenderWidgetHostViewMac::PauseForPendingResizeOrRepaintsAndDraw() {
 
   // Synchronized resizing does not yet work with browser compositor.
   // http://crbug.com/388005
-  if (delegated_frame_host_)
+  if (IsDelegatedRendererEnabled())
     return;
 
   // Pausing for one view prevents others from receiving frames.