Fix various issues with framebuffer fetch

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 776 matching lines @@
     // the abs first in a separate expression.
     if (kTegra3_GrGLRenderer == ctxInfo.renderer()) {
         glslCaps->fCanUseMinAndAbsTogether = false;
     }
 
     // On Intel GPU there is an issue where it reads the second argument to atan "- %s.x" as an int
     // thus must us -1.0 * %s.x to work correctly
     if (kIntel_GrGLVendor == ctxInfo.vendor()) {
         glslCaps->fMustForceNegatedAtanParamToFloat = true;
     }
+
+    // On Adreno devices with framebuffer fetch support, there is a bug where they always return
+    // the original dst color when reading the outColor even after being written to. By using a
+    // local outColor we can work around this bug.
+    if (glslCaps->fFBFetchSupport && kQualcomm_GrGLVendor == ctxInfo.vendor()) {
+        glslCaps->fRequiresLocalOutputColorForFBFetch = true;
+    }
 }
 
 bool GrGLCaps::hasPathRenderingSupport(const GrGLContextInfo& ctxInfo, const GrGLInterface* gli) {
     bool hasChromiumPathRendering = ctxInfo.hasExtension("GL_CHROMIUM_path_rendering");
 
     if (!(ctxInfo.hasExtension("GL_NV_path_rendering") || hasChromiumPathRendering)) {
         return false;
     }
 
     if (kGL_GrGLStandard == ctxInfo.standard()) {
@@ skipping 1133 matching lines @@
 void GrGLCaps::onApplyOptionsOverrides(const GrContextOptions& options) {
     if (options.fEnableInstancedRendering) {
         fInstancedSupport = gr_instanced::GLInstancedRendering::CheckSupport(*this);
 #ifndef SK_BUILD_FOR_MAC
         // OS X doesn't seem to write correctly to floating point textures when using
         // glDraw*Indirect, regardless of the underlying GPU.
         fAvoidInstancedDrawsToFPTargets = true;
 #endif
     }
 }