Refactor SkGLContext to be actually extendable

src/gpu/gl/SkGLContext.cpp

Index: src/gpu/gl/SkGLContext.cpp
diff --git a/src/gpu/gl/SkGLContext.cpp b/src/gpu/gl/SkGLContext.cpp
index 92f65cd924712b51470c753358fa8bff5838fb2e..7cc728d62ed9da4c3464fcfc483decccd10cf80f 100644
--- a/src/gpu/gl/SkGLContext.cpp
+++ b/src/gpu/gl/SkGLContext.cpp
@@ -8,131 +8,11 @@
 #include "gl/SkGLContext.h"
 #include "GrGLUtil.h"
 
-SkGLContext::SkGLContext()
-    : fFBO(0)
-    , fColorBufferID(0)
-    , fDepthStencilBufferID(0)
-    , fGL(NULL) {
+SkGLContext::SkGLContext() {
 }
 
 SkGLContext::~SkGLContext() {
-
-    if (fGL) {
-        // TODO: determine why DeleteFramebuffers is generating a GL error in tests
-        SK_GL_NOERRCHECK(*this, DeleteFramebuffers(1, &fFBO));
-        SK_GL_NOERRCHECK(*this, DeleteRenderbuffers(1, &fColorBufferID));
-        SK_GL_NOERRCHECK(*this, DeleteRenderbuffers(1, &fDepthStencilBufferID));
-    }
-
-    SkSafeUnref(fGL);
-}
-
-bool SkGLContext::init(GrGLStandard forcedGpuAPI, int width,
-                             int height) {
-    if (fGL) {
-        fGL->unref();
-        this->destroyGLContext();
-    }
-
-    fGL = this->createGLContext(forcedGpuAPI);
-    if (fGL) {
-        const GrGLubyte* temp;
-
-        if (!fGL->validate()) {
-            fGL = NULL;
-            this->destroyGLContext();
-            return false;
-        }
-
-        SK_GL_RET(*this, temp, GetString(GR_GL_VERSION));
-        const char* versionStr = reinterpret_cast<const char*>(temp);
-        GrGLVersion version = GrGLGetVersionFromString(versionStr);
-
-        // clear any existing GL erorrs
-        GrGLenum error;
-        do {
-            SK_GL_RET(*this, error, GetError());
-        } while (GR_GL_NO_ERROR != error);
-
-        SK_GL(*this, GenFramebuffers(1, &fFBO));
-        SK_GL(*this, BindFramebuffer(GR_GL_FRAMEBUFFER, fFBO));
-        SK_GL(*this, GenRenderbuffers(1, &fColorBufferID));
-        SK_GL(*this, BindRenderbuffer(GR_GL_RENDERBUFFER, fColorBufferID));
-        if (kGLES_GrGLStandard == this->gl()->fStandard) {
-            SK_GL(*this, RenderbufferStorage(GR_GL_RENDERBUFFER,
-                                             GR_GL_RGBA8,
-                                             width, height));
-        } else {
-            SK_GL(*this, RenderbufferStorage(GR_GL_RENDERBUFFER,
-                                             GR_GL_RGBA,
-                                             width, height));
-        }
-        SK_GL(*this, FramebufferRenderbuffer(GR_GL_FRAMEBUFFER,
-                                             GR_GL_COLOR_ATTACHMENT0,
-                                             GR_GL_RENDERBUFFER,
-                                             fColorBufferID));
-        SK_GL(*this, GenRenderbuffers(1, &fDepthStencilBufferID));
-        SK_GL(*this, BindRenderbuffer(GR_GL_RENDERBUFFER, fDepthStencilBufferID));
-
-        // Some drivers that support packed depth stencil will only succeed
-        // in binding a packed format an FBO. However, we can't rely on packed
-        // depth stencil being available.
-        bool supportsPackedDepthStencil;
-        if (kGLES_GrGLStandard == this->gl()->fStandard) {
-            supportsPackedDepthStencil = version >= GR_GL_VER(3,0) ||
-                                         this->hasExtension("GL_OES_packed_depth_stencil");
-        } else {
-            supportsPackedDepthStencil = version >= GR_GL_VER(3,0) ||
-                                         this->hasExtension("GL_EXT_packed_depth_stencil") ||
-                                         this->hasExtension("GL_ARB_framebuffer_object");
-        }
-
-        if (supportsPackedDepthStencil) {
-            // ES2 requires sized internal formats for RenderbufferStorage
-            // On Desktop we let the driver decide.
-            GrGLenum format = kGLES_GrGLStandard == this->gl()->fStandard ?
-                                    GR_GL_DEPTH24_STENCIL8 :
-                                    GR_GL_DEPTH_STENCIL;
-            SK_GL(*this, RenderbufferStorage(GR_GL_RENDERBUFFER,
-                                             format,
-                                             width, height));
-            SK_GL(*this, FramebufferRenderbuffer(GR_GL_FRAMEBUFFER,
-                                                 GR_GL_DEPTH_ATTACHMENT,
-                                                 GR_GL_RENDERBUFFER,
-                                                 fDepthStencilBufferID));
-        } else {
-            GrGLenum format = kGLES_GrGLStandard == this->gl()->fStandard ? GR_GL_STENCIL_INDEX8 :
-                                                                          GR_GL_STENCIL_INDEX;
-            SK_GL(*this, RenderbufferStorage(GR_GL_RENDERBUFFER,
-                                             format,
-                                             width, height));
-        }
-        SK_GL(*this, FramebufferRenderbuffer(GR_GL_FRAMEBUFFER,
-                                             GR_GL_STENCIL_ATTACHMENT,
-                                             GR_GL_RENDERBUFFER,
-                                             fDepthStencilBufferID));
-        SK_GL(*this, Viewport(0, 0, width, height));
-        SK_GL(*this, ClearStencil(0));
-        SK_GL(*this, Clear(GR_GL_STENCIL_BUFFER_BIT));
-
-        SK_GL_RET(*this, error, GetError());
-        GrGLenum status;
-        SK_GL_RET(*this, status, CheckFramebufferStatus(GR_GL_FRAMEBUFFER));
-
-        if (GR_GL_FRAMEBUFFER_COMPLETE != status ||
-            GR_GL_NO_ERROR != error) {
-            fFBO = 0;
-            fColorBufferID = 0;
-            fDepthStencilBufferID = 0;
-            fGL->unref();
-            fGL = NULL;
-            this->destroyGLContext();
-            return false;
-        } else {
-            return true;
-        }
-    }
-    return false;
+    SkASSERT(NULL == fGL.get());  // Subclass should destroy the interface.
 }
 
 void SkGLContext::testAbandon() {