Don't do discards when on Adreno4xx due to driver bug.

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 201 matching lines @@
     // 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() ||
          kQualcomm_GrGLVendor == ctxInfo.vendor())) {
         fUseNonVBOVertexAndIndexDynamicData = true;
     }
 
-    if ((kGL_GrGLStandard == standard && version >= GR_GL_VER(4,3)) ||
-        (kGLES_GrGLStandard == standard && version >= GR_GL_VER(3,0)) ||
-        ctxInfo.hasExtension("GL_ARB_invalidate_subdata")) {
+    // A driver but on the nexus 6 causes incorrect dst copies when invalidate is called beforehand.
+    // Thus we are blacklisting this extension for now on Adreno4xx devices.
+    if (kAdreno4xx_GrGLRenderer != ctxInfo.renderer() &&
+        ((kGL_GrGLStandard == standard && version >= GR_GL_VER(4,3)) ||
+         (kGLES_GrGLStandard == standard && version >= GR_GL_VER(3,0)) ||
+         ctxInfo.hasExtension("GL_ARB_invalidate_subdata"))) {
         fDiscardRenderTargetSupport = true;
         fInvalidateFBType = kInvalidate_InvalidateFBType;
     } else if (ctxInfo.hasExtension("GL_EXT_discard_framebuffer")) {
         fDiscardRenderTargetSupport = true;
         fInvalidateFBType = kDiscard_InvalidateFBType;
     }
 
     if (kARM_GrGLVendor == ctxInfo.vendor() || kImagination_GrGLVendor == ctxInfo.vendor()) {
         fFullClearIsFree = true;
     }
@@ skipping 917 matching lines @@
     if (fGeometryShaderSupport) {
         for (int p = 0; p < kGrSLPrecisionCount; ++p) {
             fFloatPrecisions[kGeometry_GrShaderType][p] = fFloatPrecisions[kVertex_GrShaderType][p];
         }
     }
 }