Refactor SkyShell to allow multiple SkyViews

sky/shell/ios/sky_surface.mm

 // Copyright 2015 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 "sky_surface.h"
 
 #import <QuartzCore/QuartzCore.h>
 #import <OpenGLES/EAGL.h>
 #import <OpenGLES/EAGLDrawable.h>
 
@@ skipping 20 matching lines @@
       return sky::EVENT_TYPE_POINTER_CANCEL;
   }
 
   return sky::EVENT_TYPE_UNKNOWN;
 }
 
 @implementation SkySurface {
   BOOL _platformViewInitialized;
 
   sky::ViewportObserverPtr _viewport_observer;
+  scoped_ptr<sky::shell::Instance> _instance;
+}
+
+-(instancetype) initWithSkyInstance:(sky::shell::Instance *) instance {
+  self = [super init];
+  if (self)
+    _instance.reset(instance);
+  return self;
 }
 
 - (gfx::AcceleratedWidget)acceleratedWidget {
   return (gfx::AcceleratedWidget)self.layer;
 }
 
 - (void)layoutSubviews {
   [super layoutSubviews];
 
   [self configureLayerDefaults];
@@ skipping 22 matching lines @@
     return;
   }
 
   _platformViewInitialized = YES;
 
   [self notifySurfaceCreation];
   [self connectToViewportObserverAndLoad];
 }
 
 - (sky::shell::PlatformViewIOS*)platformView {
-  auto view = static_cast<sky::shell::PlatformViewIOS*>(
-      sky::shell::Shell::Shared().view());
+  auto view = static_cast<sky::shell::PlatformViewIOS*>(_instance->view());
   DCHECK(view);
   return view;
 }
 
 - (void)notifySurfaceCreation {
   self.platformView->SurfaceCreated(self.acceleratedWidget);
 }
 
 - (NSString*)skyInitialLoadURL {
   return [NSBundle mainBundle].infoDictionary[@"com.google.sky.load_url"];
 }
 
 - (void)connectToViewportObserverAndLoad {
-  auto view = sky::shell::Shell::Shared().view();
+  auto view = static_cast<sky::shell::PlatformViewIOS*>(_instance->view());
   auto interface_request = mojo::GetProxy(&_viewport_observer);
   view->ConnectToViewportObserver(interface_request.Pass());
 
   mojo::String string(self.skyInitialLoadURL.UTF8String);
   _viewport_observer->LoadURL(string);
 }
 
 - (void)notifySurfaceDestruction {
   self.platformView->SurfaceDestroyed();
 }
@@ skipping 44 matching lines @@
 + (Class)layerClass {
   return [CAEAGLLayer class];
 }
 
 - (void)dealloc {
   [self notifySurfaceDestruction];
   [super dealloc];
 }
 
 @end