Fix readback of 565 on Mac and enable tests

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 "GrGLGLSL.h"
 #include "GrGLStencilAttachment.h"
@@ skipping 2585 matching lines @@
                     ElevateDrawPreference(drawPreference, kRequireDraw_DrawPreference);
                     tempDrawInfo->fTempSurfaceDesc.fConfig = cpuTempConfig;
                     tempDrawInfo->fReadConfig = kAlpha_8_GrPixelConfig;
                 } else {
                     return false;
                 }
             } else {
                 SkASSERT(tempDrawInfo->fTempSurfaceDesc.fConfig == srcConfig);
                 SkASSERT(tempDrawInfo->fReadConfig == kAlpha_8_GrPixelConfig);
             }
+        } else if (this->caps()->isConfigRenderable(readConfig, false) &&
+                   this->readPixelsSupported(readConfig, readConfig)) {
+            // Do a draw to convert from the src config to the read config.
+            ElevateDrawPreference(drawPreference, kRequireDraw_DrawPreference);
+            tempDrawInfo->fTempSurfaceDesc.fConfig = readConfig;
+            tempDrawInfo->fReadConfig = readConfig;
         } else {
             return false;
         }
     }
 
     if (srcAsRT &&
         read_pixels_pays_for_y_flip(srcAsRT, this->glCaps(), width, height, readConfig, rowBytes)) {
         ElevateDrawPreference(drawPreference, kGpuPrefersDraw_DrawPreference);
     }
 
@@ skipping 1730 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;
 }