Refactor SkyShell to allow multiple SkyViews

sky/shell/android/platform_view_android.cc

Index: sky/shell/android/platform_view_android.cc
diff --git a/sky/shell/android/platform_view_android.cc b/sky/shell/android/platform_view_android.cc
index a27246743eec20c8bc7d562f87de0e208ce1a056..8696f28b7fd480bbf20e6040ece5e098e64c3f7d 100644
--- a/sky/shell/android/platform_view_android.cc
+++ b/sky/shell/android/platform_view_android.cc
@@ -11,17 +11,20 @@
 #include "base/bind.h"
 #include "base/location.h"
 #include "jni/PlatformViewAndroid_jni.h"
+#include "sky/shell/instance.h"
 #include "sky/shell/shell.h"
 
 namespace sky {
 namespace shell {
 
 static jlong Attach(JNIEnv* env, jclass clazz, jint viewportObserverHandle) {
-  PlatformView* view = Shell::Shared().view();
+  Instance* instance = new Instance(Shell::Shared());
+  auto view = static_cast<PlatformViewAndroid*>(instance->view());
+  view->SetInstance(make_scoped_ptr(instance));
   view->ConnectToViewportObserver(
       mojo::MakeRequest<ViewportObserver>(mojo::ScopedMessagePipeHandle(
           mojo::MessagePipeHandle(viewportObserverHandle))));
-  return reinterpret_cast<jlong>(view);
+  return reinterpret_cast<jlong>(instance->view());
 }
 
 // static
@@ -29,6 +32,14 @@ bool PlatformViewAndroid::Register(JNIEnv* env) {
   return RegisterNativesImpl(env);
 }
 
+PlatformView* PlatformView::Create(const Config& config) {
+  return new PlatformViewAndroid(config);
+}
+
+PlatformViewAndroid::PlatformViewAndroid(const Config& config)
+  : PlatformView(config) {
+}
+
 PlatformViewAndroid::~PlatformViewAndroid() {
   if (window_)
     ReleaseWindow();
@@ -36,6 +47,8 @@ PlatformViewAndroid::~PlatformViewAndroid() {
 
 void PlatformViewAndroid::Detach(JNIEnv* env, jobject obj) {
   DCHECK(!window_);
+  instance_.reset();
+  // Note: |this| has been destroyed at this point.
 }
 
 void PlatformViewAndroid::SurfaceCreated(JNIEnv* env, jobject obj, jobject jsurface) {
@@ -56,6 +69,11 @@ void PlatformViewAndroid::SurfaceDestroyed(JNIEnv* env, jobject obj) {
   ReleaseWindow();
 }
 
+void PlatformViewAndroid::SetInstance(scoped_ptr<Instance> instance) {
+  DCHECK(!instance_);
+  instance_ = instance.Pass();
+}
+
 void PlatformViewAndroid::ReleaseWindow() {
   ANativeWindow_release(window_);
   window_ = nullptr;