[Mac] Allow vibrancy & transparency on WebContentsView

content/browser/web_contents/web_contents_view_mac.mm

 // Copyright (c) 2012 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #import <Carbon/Carbon.h>
 
 #import "content/browser/web_contents/web_contents_view_mac.h"
 
 #include <string>
 
@@ skipping 405 matching lines @@
   [self cancelDeferredClose];
 
   // This probably isn't strictly necessary, but can't hurt.
   [self unregisterDraggedTypes];
 
   [[NSNotificationCenter defaultCenter] removeObserver:self];
 
   [super dealloc];
 }
 
+- (BOOL)allowsVibrancy {
+  // Returning YES will allow rendering this view with vibrancy effect if it is
+  // incorporated into a view hierarchy that uses vibrancy, it will have no
+  // effect otherwise.
+  // For details see Apple documentation on NSView and NSVisualEffectView.
+  return YES;
+}
+
 // Registers for the view for the appropriate drag types.
 - (void)registerDragTypes {
   NSArray* types = [NSArray arrayWithObjects:
       ui::kChromeDragDummyPboardType,
       kWebURLsWithTitlesPboardType,
       NSURLPboardType,
       NSStringPboardType,
       NSHTMLPboardType,
       NSRTFPboardType,
       NSFilenamesPboardType,
@@ skipping 36 matching lines @@
 - (BOOL)mouseDownCanMoveWindow {
   // This is needed to prevent mouseDowns from moving the window
   // around.  The default implementation returns YES only for opaque
   // views.  WebContentsViewCocoa does not draw itself in any way, but
   // its subviews do paint their entire frames.  Returning NO here
   // saves us the effort of overriding this method in every possible
   // subview.
   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];
 }
 
 - (void)startDragWithDropData:(const DropData&)dropData
             dragOperationMask:(NSDragOperation)operationMask
                         image:(NSImage*)image
                        offset:(NSPoint)offset {
   dragSource_.reset([[WebDragSource alloc]
@@ skipping 138 matching lines @@
   if (window && webContents) {
     if ([window occlusionState] & NSWindowOcclusionStateVisible) {
       webContents->WasUnOccluded();
     } else {
       webContents->WasOccluded();
     }
   }
 }
 
 @end