Add passthrough GP for cases where no color or coverage should be emitted by GP

src/gpu/GrAtlasTextContext.cpp

Index: src/gpu/GrAtlasTextContext.cpp
diff --git a/src/gpu/GrAtlasTextContext.cpp b/src/gpu/GrAtlasTextContext.cpp
index 108d63c919b944afd5446ef6a58168a6949b7ef4..ff841ecbb21882992a28b85926aac323cadda4eb 100644
--- a/src/gpu/GrAtlasTextContext.cpp
+++ b/src/gpu/GrAtlasTextContext.cpp
@@ -1581,12 +1581,16 @@ private:
                                             texture));
         } else {
             GrTextureParams params(SkShader::kClamp_TileMode, GrTextureParams::kNone_FilterMode);
-            gp.reset(GrBitmapTextGeoProc::Create(this->color(),
-                                                 texture,
-                                                 params,
-                                                 maskFormat,
-                                                 localMatrix,
-                                                 this->usesLocalCoords()));
+            if ((maskFormat == kARGB_GrMaskFormat && fBatch.fColorIgnored)) {
+                gp.reset(GrGeometryProcessor::CreatePassthroughGP(kColorTextVASize));
+            } else {
+                gp.reset(GrBitmapTextGeoProc::Create(this->color(),
+                                                     texture,
+                                                     params,
+                                                     maskFormat,
+                                                     localMatrix,
+                                                     this->usesLocalCoords()));
+            }
         }
 
         FlushInfo flushInfo;