Remove support for GL discards

src/gpu/gl/GrGLGpu.cpp

 /*
  * Copyright 2011 Google Inc.
  *
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file.
  */
 
 #include "GrGLGpu.h"
 #include "GrGLBuffer.h"
 #include "GrGLGLSL.h"
@@ skipping 2158 matching lines @@
     r = GrColorUnpackR(color) * scaleRGB;
     g = GrColorUnpackG(color) * scaleRGB;
     b = GrColorUnpackB(color) * scaleRGB;
 
     GL_CALL(ColorMask(GR_GL_TRUE, GR_GL_TRUE, GR_GL_TRUE, GR_GL_TRUE));
     fHWWriteToColor = kYes_TriState;
     GL_CALL(ClearColor(r, g, b, a));
     GL_CALL(Clear(GR_GL_COLOR_BUFFER_BIT));
 }
 
-void GrGLGpu::discard(GrRenderTarget* renderTarget) {
-    SkASSERT(renderTarget);
-    if (!this->caps()->discardRenderTargetSupport()) {
-        return;
-    }
-
-    GrGLRenderTarget* glRT = static_cast<GrGLRenderTarget*>(renderTarget);
-    if (renderTarget->getUniqueID() != fHWBoundRenderTargetUniqueID) {
-        fHWBoundRenderTargetUniqueID = SK_InvalidUniqueID;
-        fStats.incRenderTargetBinds();
-        GL_CALL(BindFramebuffer(GR_GL_FRAMEBUFFER, glRT->renderFBOID()));
-    }
-    switch (this->glCaps().invalidateFBType()) {
-        case GrGLCaps::kNone_InvalidateFBType:
-            SkFAIL("Should never get here.");
-            break;
-        case GrGLCaps::kInvalidate_InvalidateFBType:
-            if (0 == glRT->renderFBOID()) {
-                //  When rendering to the default framebuffer the legal values for attachments
-                //  are GL_COLOR, GL_DEPTH, GL_STENCIL, ... rather than the various FBO attachment
-                //  types.
-                static const GrGLenum attachments[] = { GR_GL_COLOR };
-                GL_CALL(InvalidateFramebuffer(GR_GL_FRAMEBUFFER, SK_ARRAY_COUNT(attachments),
-                        attachments));
-            } else {
-                static const GrGLenum attachments[] = { GR_GL_COLOR_ATTACHMENT0 };
-                GL_CALL(InvalidateFramebuffer(GR_GL_FRAMEBUFFER, SK_ARRAY_COUNT(attachments),
-                        attachments));
-            }
-            break;
-        case GrGLCaps::kDiscard_InvalidateFBType: {
-            if (0 == glRT->renderFBOID()) {
-                //  When rendering to the default framebuffer the legal values for attachments
-                //  are GL_COLOR, GL_DEPTH, GL_STENCIL, ... rather than the various FBO attachment
-                //  types. See glDiscardFramebuffer() spec.
-                static const GrGLenum attachments[] = { GR_GL_COLOR };
-                GL_CALL(DiscardFramebuffer(GR_GL_FRAMEBUFFER, SK_ARRAY_COUNT(attachments),
-                        attachments));
-            } else {
-                static const GrGLenum attachments[] = { GR_GL_COLOR_ATTACHMENT0 };
-                GL_CALL(DiscardFramebuffer(GR_GL_FRAMEBUFFER, SK_ARRAY_COUNT(attachments),
-                        attachments));
-            }
-            break;
-        }
-    }
-    renderTarget->flagAsResolved();
-}
-
 void GrGLGpu::clearStencil(GrRenderTarget* target) {
     if (nullptr == target) {
         return;
     }
     GrGLRenderTarget* glRT = static_cast<GrGLRenderTarget*>(target);
     this->flushRenderTarget(glRT, &SkIRect::EmptyIRect());
 
     this->disableScissor();
 
     GL_CALL(StencilMask(0xffffffff));
@@ skipping 2413 matching lines @@
         if (GR_GL_TEXTURE_EXTERNAL == glTexture->target() ||
             GR_GL_TEXTURE_RECTANGLE == glTexture->target()) {
             copyParams->fFilter = GrTextureParams::kNone_FilterMode;
             copyParams->fWidth = texture->width();
             copyParams->fHeight = texture->height();
             return true;
         }
     }
     return false;
 }