[Mac] Allow vibrancy & transparency on WebContentsView

content/browser/web_contents/web_contents_view_mac.mm

Index: content/browser/web_contents/web_contents_view_mac.mm
diff --git a/content/browser/web_contents/web_contents_view_mac.mm b/content/browser/web_contents/web_contents_view_mac.mm
index 27989c3951ffce334f0a2f48c2db99b67f3695df..24bce2c586bf4fbd1ba8917993ceee1d1cc09a84 100644
--- a/content/browser/web_contents/web_contents_view_mac.mm
+++ b/content/browser/web_contents/web_contents_view_mac.mm
@@ -423,6 +423,10 @@ void WebContentsViewMac::CloseTab() {
   [super dealloc];
 }
 
+- (BOOL)allowsVibrancy {
+  return YES;

[Alexei Svitkine (slow), 2015/01/22 16:41:21]

What's the effect of returning YES here?

Does it change behavior by default or is it dependent on something else? (e.g.
the view being opaque)

If it doesn't change anything on its own, please document that here in a
comment.

(If it does change things, then probably we should make it configurable unless
Chrome decides to actually adopt the changed behavior/appearance.)

[joleksy, 2015/01/23 07:24:01]

By itself it does not change anything, from the documentation:
"AppKit checks this property when the view is incorporated into a view hierarchy
that uses vibrancy."
This means that in order to actually change how this view looks it would have to
be put inside a vibrant hierarchy (i.e. within NSVisualEffectView).
I will add comment.

+}
+
 // Registers for the view for the appropriate drag types.
 - (void)registerDragTypes {
   NSArray* types = [NSArray arrayWithObjects:
@@ -479,6 +483,13 @@ void WebContentsViewMac::CloseTab() {
   return mouseDownCanMoveWindow_;
 }
 
+- (void)setOpaque:(BOOL)opaque {
+  RenderWidgetHostViewMac* view = static_cast<RenderWidgetHostViewMac*>(
+      webContentsView_->web_contents()->GetRenderWidgetHostView());
+  DCHECK(view);
+  [view->cocoa_view() setOpaque:opaque];
+}
+
 - (void)pasteboard:(NSPasteboard*)sender provideDataForType:(NSString*)type {
   [dragSource_ lazyWriteToPasteboard:sender
                              forType:type];