opengl renderer: create rendering subwindow

The application provides the window handle to which the
OpenglRenderer should render to however only a sub-region of
this window needs to be rendered. This change adds this functionality
by creating a native child subwindow into which rendering will happen.

tools/emulator/opengl/host/libs/libOpenglRender/NativeMacSubWindow.m

@@ -0,0 +1,37 @@
+/*
+* Copyright (C) 2011 The Android Open Source Project
+*
+* Licensed under the Apache License, Version 2.0 (the "License");
+* you may not use this file except in compliance with the License.
+* You may obtain a copy of the License at
+*
+* http://www.apache.org/licenses/LICENSE-2.0
+*
+* Unless required by applicable law or agreed to in writing, software
+* distributed under the License is distributed on an "AS IS" BASIS,
+* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+* See the License for the specific language governing permissions and
+* limitations under the License.
+*/
+#include "NativeSubWindow.h"
+#include <Cocoa/Cocoa.h>
+
+
+EGLNativeWindowType createSubWindow(FBNativeWindowType p_window,
+                                    EGLNativeDisplayType* display_out,
+                                    int x, int y,int width, int height){
+    NSRect contentRect = NSMakeRect(x, y, width, height);
+    NSView *glView = [[NSView alloc] initWithFrame:contentRect];
+    if (glView) {
+        NSWindow *win = (NSWindow *)p_window;
+        [[win contentView] addSubview:glView];
+        [win makeKeyAndOrderFront:nil];
+        }
+    return (EGLNativeWindowType)glView;
+}
+
+void destroySubWindow(EGLNativeDisplayType dis,EGLNativeWindowType win){
+    if(win){
+        delete  win;
+    }
+}