Add flag bits for partial GrContext reset

src/gpu/GrGpu.h

Index: src/gpu/GrGpu.h
diff --git a/src/gpu/GrGpu.h b/src/gpu/GrGpu.h
index 3acfac2703e6d25dd45f8d51539db636a6bc858a..a2cddf509c55557b975edf22d98c49a86f15d7f1 100644
--- a/src/gpu/GrGpu.h
+++ b/src/gpu/GrGpu.h
@@ -66,7 +66,10 @@ public:
      * the GrGpu that the state was modified and it shouldn't make assumptions
      * about the state.
      */
-    void markContextDirty() { fContextIsDirty = true; }
+    void markContextDirty(uint32_t state = GrContext::kALL_GLBackendState) {
+        fContextIsDirty = true;
+        fResetBits |= state;
+    }
 
     void unimpl(const char[]);
 
@@ -426,7 +429,7 @@ private:
 
     // called when the 3D context state is unknown. Subclass should emit any
     // assumed 3D context state and dirty any state cache.
-    virtual void onResetContext() = 0;
+    virtual void onResetContext(uint32_t resetBits) = 0;
 
     // overridden by backend-specific derived class to create objects.
     virtual GrTexture* onCreateTexture(const GrTextureDesc& desc,
@@ -507,7 +510,8 @@ private:
         // stencil buffer. Perhaps we should detect whether it is a
         // internally created stencil buffer and if so skip the invalidate.
         fClipMaskManager.invalidateStencilMask();
-        this->onResetContext();
+        this->onResetContext(fResetBits);
+        fResetBits = 0;
         ++fResetTimestamp;
     }
 
@@ -532,6 +536,7 @@ private:
     // these are mutable so they can be created on-demand
     mutable GrIndexBuffer*                                              fQuadIndexBuffer;
     bool                                                                fContextIsDirty;
+    uint32_t                                                            fResetBits;
     // Used to abandon/release all resources created by this GrGpu. TODO: Move this
     // functionality to GrResourceCache.
     ResourceList                                                        fResourceList;