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

src/gpu/gl/iOS/SkNativeGLContext_iOS.mm

Index: src/gpu/gl/iOS/SkNativeGLContext_iOS.mm
diff --git a/src/gpu/gl/iOS/SkNativeGLContext_iOS.mm b/src/gpu/gl/iOS/SkNativeGLContext_iOS.mm
new file mode 100644
index 0000000000000000000000000000000000000000..1bdaf70f1c37c60fb47caecda58ece76a8acbb04
--- /dev/null
+++ b/src/gpu/gl/iOS/SkNativeGLContext_iOS.mm
@@ -0,0 +1,71 @@
+
+/*
+ * 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/SkNativeGLContext.h"
+#import <OpenGLES/EAGL.h>
+
+#define EAGLCTX ((EAGLContext*)(fEAGLContext))
+
+SkNativeGLContext::AutoContextRestore::AutoContextRestore() {
+    fEAGLContext = [EAGLContext currentContext];
+    if (EAGLCTX) {
+        [EAGLCTX retain];
+    }
+}
+
+SkNativeGLContext::AutoContextRestore::~AutoContextRestore() {
+    if (EAGLCTX) {
+        [EAGLContext setCurrentContext:EAGLCTX];
+        [EAGLCTX release];
+    }
+}
+
+///////////////////////////////////////////////////////////////////////////////
+
+SkNativeGLContext::SkNativeGLContext()
+    : fEAGLContext(NULL) {
+}
+
+SkNativeGLContext::~SkNativeGLContext() {
+    this->destroyGLContext();
+}
+
+void SkNativeGLContext::destroyGLContext() {
+    if (fEAGLContext) {
+        if ([EAGLContext currentContext] == EAGLCTX) {
+            [EAGLContext setCurrentContext:nil];
+        }
+        [EAGLCTX release];
+        fEAGLContext = NULL;
+    }
+}
+
+const GrGLInterface* SkNativeGLContext::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 SkNativeGLContext::makeCurrent() const {
+    if (![EAGLContext setCurrentContext:EAGLCTX]) {
+        SkDebugf("Could not set the context.\n");
+    }
+}
+
+void SkNativeGLContext::swapBuffers() const { }