Add discard API to SkCanvas, plumb it to glDiscardFramebuffer()

src/gpu/gl/GrGLCaps.cpp

 /*
  * 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 "GrGLCaps.h"
 #include "GrGLContext.h"
@@ skipping 27 matching lines @@
     fTextureUsageSupport = false;
     fTexStorageSupport = false;
     fTextureRedSupport = false;
     fImagingSupport = false;
     fTwoFormatLimit = false;
     fFragCoordsConventionSupport = false;
     fVertexArrayObjectSupport = false;
     fUseNonVBOVertexAndIndexDynamicData = false;
     fIsCoreProfile = false;
     fFixedFunctionSupport = false;
-    fDiscardFBSupport = false;
     fFullClearIsFree = false;
 }
 
 GrGLCaps::GrGLCaps(const GrGLCaps& caps) : GrDrawTargetCaps() {
     *this = caps;
 }
 
 GrGLCaps& GrGLCaps::operator = (const GrGLCaps& caps) {
     INHERITED::operator=(caps);
     fVerifiedColorConfigs = caps.fVerifiedColorConfigs;
@@ skipping 16 matching lines @@
     fTextureUsageSupport = caps.fTextureUsageSupport;
     fTexStorageSupport = caps.fTexStorageSupport;
     fTextureRedSupport = caps.fTextureRedSupport;
     fImagingSupport = caps.fImagingSupport;
     fTwoFormatLimit = caps.fTwoFormatLimit;
     fFragCoordsConventionSupport = caps.fFragCoordsConventionSupport;
     fVertexArrayObjectSupport = caps.fVertexArrayObjectSupport;
     fUseNonVBOVertexAndIndexDynamicData = caps.fUseNonVBOVertexAndIndexDynamicData;
     fIsCoreProfile = caps.fIsCoreProfile;
     fFixedFunctionSupport = caps.fFixedFunctionSupport;
-    fDiscardFBSupport = caps.fDiscardFBSupport;
     fFullClearIsFree = caps.fFullClearIsFree;
 
     return *this;
 }
 
 void GrGLCaps::init(const GrGLContextInfo& ctxInfo, const GrGLInterface* gli) {
 
     this->reset();
     if (!ctxInfo.isInitialized()) {
         return;
@@ skipping 119 matching lines @@
 
     // SGX and Mali GPUs that are based on a tiled-deferred architecture that have trouble with
     // frequently changing VBOs. We've measured a performance increase using non-VBO vertex
     // data for dynamic content on these GPUs. Perhaps we should read the renderer string and
     // limit this decision to specific GPU families rather than basing it on the vendor alone.
     if (!GR_GL_MUST_USE_VBO &&
         (kARM_GrGLVendor == ctxInfo.vendor() || kImagination_GrGLVendor == ctxInfo.vendor())) {
         fUseNonVBOVertexAndIndexDynamicData = true;
     }
 
-    fDiscardFBSupport = ctxInfo.hasExtension("GL_EXT_discard_framebuffer");
+    fDiscardRenderTargetSupport = ctxInfo.hasExtension("GL_EXT_discard_framebuffer");
 
     if (kARM_GrGLVendor == ctxInfo.vendor() || kImagination_GrGLVendor == ctxInfo.vendor()) {
         fFullClearIsFree = true;
     }
 
     if (kGL_GrGLStandard == standard) {
         fVertexArrayObjectSupport = version >= GR_GL_VER(3, 0) ||
                                     ctxInfo.hasExtension("GL_ARB_vertex_array_object");
     } else {
         fVertexArrayObjectSupport = version >= GR_GL_VER(3, 0) ||
@@ skipping 416 matching lines @@
     r.appendf("Texture Usage support: %s\n", (fTextureUsageSupport ? "YES": "NO"));
     r.appendf("Texture Storage support: %s\n", (fTexStorageSupport ? "YES": "NO"));
     r.appendf("GL_R support: %s\n", (fTextureRedSupport ? "YES": "NO"));
     r.appendf("GL_ARB_imaging support: %s\n", (fImagingSupport ? "YES": "NO"));
     r.appendf("Two Format Limit: %s\n", (fTwoFormatLimit ? "YES": "NO"));
     r.appendf("Fragment coord conventions support: %s\n",
              (fFragCoordsConventionSupport ? "YES": "NO"));
     r.appendf("Vertex array object support: %s\n", (fVertexArrayObjectSupport ? "YES": "NO"));
     r.appendf("Use non-VBO for dynamic data: %s\n",
              (fUseNonVBOVertexAndIndexDynamicData ? "YES" : "NO"));
-    r.appendf("Discard FrameBuffer support: %s\n", (fDiscardFBSupport ? "YES" : "NO"));
     r.appendf("Full screen clear is free: %s\n", (fFullClearIsFree ? "YES" : "NO"));
     return r;
 }