Fix various issues with framebuffer fetch

src/gpu/gl/GrGLCaps.cpp

Index: src/gpu/gl/GrGLCaps.cpp
diff --git a/src/gpu/gl/GrGLCaps.cpp b/src/gpu/gl/GrGLCaps.cpp
index 4d856ac9320d9b1b58e5a3e9f0d1d8b1eb4583d9..b93d50b4d98f9b877dca013e1229b2dc6cb450dc 100644
--- a/src/gpu/gl/GrGLCaps.cpp
+++ b/src/gpu/gl/GrGLCaps.cpp
@@ -794,6 +794,13 @@ void GrGLCaps::initGLSL(const GrGLContextInfo& ctxInfo) {
     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) {