added support for PLS path rendering

src/gpu/gl/GrGLGpu.h

Index: src/gpu/gl/GrGLGpu.h
diff --git a/src/gpu/gl/GrGLGpu.h b/src/gpu/gl/GrGLGpu.h
index 63f1247962b0677475c01da0e1fc7dcf3b06a81d..6f194dcd6c4296ebaebb0b1ec5ba86f6329e6d43 100644
--- a/src/gpu/gl/GrGLGpu.h
+++ b/src/gpu/gl/GrGLGpu.h
@@ -134,6 +134,8 @@ public:
 
     void drawDebugWireRect(GrRenderTarget*, const SkIRect&, GrColor) override;
 
+    void performFlushWorkaround() override;
+
 private:
     GrGLGpu(GrGLContext* ctx, GrContext* context);
 
@@ -234,6 +236,11 @@ private:
                                       const SkIRect& srcRect,
                                       const SkIPoint& dstPoint);
 
+    void stampRectUsingProgram(GrGLuint program, const SkRect& bounds, GrGLint posXformUniform, 
+                               GrGLuint arrayBuffer);
+
+    void setupPixelLocalStorage(const DrawArgs& args);
+
     static bool BlendCoeffReferencesConstant(GrBlendCoeff coeff);
 
     class ProgramCache : public ::SkNoncopyable {
@@ -355,6 +362,8 @@ private:
     void createWireRectProgram();
     void createUnitRectBuffer();
 
+    void createPLSSetupProgram();
+
     // GL program-related state
     ProgramCache*               fProgramCache;
 
@@ -565,6 +574,15 @@ private:
         }
     }
 
+    struct {
+        GrGLuint    fProgram;
+        GrGLint     fPosXformUniform;
+        GrGLuint    fArrayBuffer;
+    } fPLSSetupProgram;
+
+    bool fHWPLSEnabled;
+    bool fPLSHasBeenUsed;
+
     typedef GrGpu INHERITED;
     friend class GrGLPathRendering; // For accessing setTextureUnit.
 };