Reset context after doing non-Skia GL rendering.

bench/GLBench.cpp

 /*
  * Copyright 2015 Google Inc.
  *
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file.
  */
 
 #include "GLBench.h"
 
 #if SK_SUPPORT_GPU
@@ skipping 38 matching lines @@
     }
     this->teardown(ctx->interface());
 }
 
 void GLBench::onDraw(int loops, SkCanvas* canvas) {
     const GrGLContext* ctx = this->getGLContext(canvas);
     if (!ctx) {
         return;
     }
     this->glDraw(loops, ctx);
+    canvas->getGrContext()->resetContext();
 }
 
 GrGLuint GLBench::CompileShader(const GrGLInterface* gl, const char* shaderSrc, GrGLenum type) {
     GrGLuint shader;
     // Create the shader object
     GR_GL_CALL_RET(gl, shader, CreateShader(type));
 
     // Load the shader source
     GR_GL_CALL(gl, ShaderSource(shader, 1, &shaderSrc, nullptr));
 
@@ skipping 94 matching lines @@
     bm.setPixels(readback.get());
 
     if (!SkImageEncoder::EncodeFile(filename, bm, SkImageEncoder::kPNG_Type, 100)) {
         SkDebugf("------ failed to encode %s\n", filename);
         remove(filename);   // remove any partial file
         return;
     }
 }
 
 #endif