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 8c127f641908b856fb07004286f2f1951aee2c7b..3333b92864834778a240dfab5eff5aa61ded3ff9 100644
--- a/src/gpu/gl/GrGLGpu.h
+++ b/src/gpu/gl/GrGLGpu.h
@@ -133,6 +133,8 @@ public:
 
     void drawDebugWireRect(GrRenderTarget*, const SkIRect&, GrColor) override;
 
+    void performFlushWorkaround() override;
+
 private:
     GrGLGpu(GrGLContext* ctx, GrContext* context);
 
@@ -212,6 +214,11 @@ 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 {
@@ -328,6 +335,8 @@ private:
     void createWireRectProgram();
     void createUnitRectBuffer();
 
+    void createPLSSetupProgram();
+
     // GL program-related state
     ProgramCache*               fProgramCache;
 
@@ -533,6 +542,16 @@ private:
         }
     }
 
+    #ifdef ENABLE_PLS
+    struct {
+        GrGLuint    fProgram;
+        GrGLint     fPosXformUniform;
+        GrGLuint    fArrayBuffer;
+    } fPLSSetupProgram;
+
+    bool                        fHWPLSEnabled;

[bsalomon, 2016/01/04 15:33:47]

Any possibility this is in an unknown state, say after non Skia code uses the
OGL context?

+    #endif
+
     typedef GrGpu INHERITED;
     friend class GrGLPathRendering; // For accessing setTextureUnit.
 };