Revert of Make the Sk GL context class an abstract base class

src/gpu/gl/iOS/SkCreatePlatformGLContext_iOS.mm

-
-/*
- * Copyright 2012 Google Inc.
- *
- * Use of this source code is governed by a BSD-style license that can be
- * found in the LICENSE file.
- */
-
-#include "gl/SkGLContext.h"
-#import <OpenGLES/EAGL.h>
-
-#define EAGLCTX ((EAGLContext*)(fEAGLContext))
-
-namespace {
-
-class IOSNativeGLContext : public SkNativeGLContext {
-public:
-    IOSNativeGLContext();
-
-    virtual ~IOSNativeGLContext();
-
-    virtual void makeCurrent() const SK_OVERRIDE;
-    virtual void swapBuffers() const SK_OVERRIDE;
-protected:
-    virtual const GrGLInterface* createGLContext(GrGLStandard forcedGpuAPI) SK_OVERRIDE;
-    virtual void destroyGLContext() SK_OVERRIDE;
-
-private:
-    void* fEAGLContext;
-};
-
-IOSNativeGLContext::IOSNativeGLContext()
-    : fEAGLContext(NULL) {
-}
-
-IOSNativeGLContext::~IOSNativeGLContext() {
-    this->destroyGLContext();
-}
-
-void IOSNativeGLContext::destroyGLContext() {
-    if (fEAGLContext) {
-        if ([EAGLContext currentContext] == EAGLCTX) {
-            [EAGLContext setCurrentContext:nil];
-        }
-        [EAGLCTX release];
-        fEAGLContext = NULL;
-    }
-}
-
-const GrGLInterface* IOSNativeGLContext::createGLContext(GrGLStandard forcedGpuAPI) {
-    if (kGL_GrGLStandard == forcedGpuAPI) {
-        return NULL;
-    }
-
-    fEAGLContext = [[EAGLContext alloc] initWithAPI:kEAGLRenderingAPIOpenGLES2];
-    [EAGLContext setCurrentContext:EAGLCTX];
-    
-    const GrGLInterface* interface = GrGLCreateNativeInterface();
-    if (!interface) {
-        SkDebugf("Failed to create gl interface");
-        this->destroyGLContext();
-        return NULL;
-    }
-    return interface;
-}
-
-void IOSNativeGLContext::makeCurrent() const {
-    if (![EAGLContext setCurrentContext:EAGLCTX]) {
-        SkDebugf("Could not set the context.\n");
-    }
-}
-
-void IOSNativeGLContext::swapBuffers() const { }
-
-} // anonymous namespace
-
-
-SkNativeGLContext* SkCreatePlatformGLContext() {
-    return SkNEW(IOSNativeGLContext);
-}
-