Move some work from backend onClear to base class clear

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"
 
@@ skipping 29 matching lines @@
     fTwoFormatLimit = false;
     fFragCoordsConventionSupport = false;
     fVertexArrayObjectSupport = false;
     fInstancedDrawingSupport = false;
     fDirectStateAccessSupport = false;
     fDebugSupport = false;
     fES2CompatibilitySupport = false;
     fMultisampleDisableSupport = false;
     fUseNonVBOVertexAndIndexDynamicData = false;
     fIsCoreProfile = false;
-    fFullClearIsFree = false;
     fBindFragDataLocationSupport = false;
     fSRGBWriteControl = false;
     fRGBA8888PixelsOpsAreSlow = false;
     fPartialFBOReadIsSlow = false;
 
     fReadPixelsSupportedCache.reset();
 
     fShaderCaps.reset(SkNEW_ARGS(GrGLSLCaps, (contextOptions)));
 
     this->init(contextOptions, ctxInfo, glInterface);
@@ skipping 1075 matching lines @@
     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("Instanced drawing support: %s\n", (fInstancedDrawingSupport ? "YES": "NO"));
     r.appendf("Direct state access support: %s\n", (fDirectStateAccessSupport ? "YES": "NO"));
     r.appendf("Debug support: %s\n", (fDebugSupport ? "YES": "NO"));
     r.appendf("Multisample disable support: %s\n", (fMultisampleDisableSupport ? "YES" : "NO"));
     r.appendf("Use non-VBO for dynamic data: %s\n",
              (fUseNonVBOVertexAndIndexDynamicData ? "YES" : "NO"));
-    r.appendf("Full screen clear is free: %s\n", (fFullClearIsFree ? "YES" : "NO"));
     r.appendf("SRGB write contol: %s\n", (fSRGBWriteControl ? "YES" : "NO"));
     r.appendf("RGBA 8888 pixel ops are slow: %s\n", (fRGBA8888PixelsOpsAreSlow? "YES" : "NO"));
     r.appendf("Partial FBO read is slow: %s\n", (fPartialFBOReadIsSlow? "YES" : "NO"));
     return r;
 }
 
 static GrGLenum precision_to_gl_float_type(GrSLPrecision p) {
     switch (p) {
     case kLow_GrSLPrecision:
         return GR_GL_LOW_FLOAT;
@@ skipping 73 matching lines @@
         for (int p = 0; p < kGrSLPrecisionCount; ++p) {
             glslCaps->fFloatPrecisions[kGeometry_GrShaderType][p] = 
                                                glslCaps->fFloatPrecisions[kVertex_GrShaderType][p];
         }
     }
 }