Add glBlendBarrierKHR to Skia's GL bindings.

BUG=480534

TBR=sievers@chromium.org

Review URL: https://codereview.chromium.org/1097153003

Cr-Commit-Position: refs/heads/master@{#326731}

gpu/skia_bindings/gl_bindings_skia_cmd_buffer.cc

@@ -29,6 +29,7 @@ GrGLInterface* CreateCommandBufferSkiaGLBinding() {
   functions->fBindBuffer = glBindBuffer;
   functions->fBindTexture = glBindTexture;
   functions->fBindVertexArray = glBindVertexArrayOES;
+  functions->fBlendBarrier = glBlendBarrierKHR;
   functions->fBlendColor = glBlendColor;
   functions->fBlendEquation = glBlendEquation;
   functions->fBlendFunc = glBlendFunc;

ui/gl/gl_bindings_skia_in_process.cc

@@ -64,6 +64,10 @@ GLvoid StubGLBindVertexArray(GLuint array) {
   glBindVertexArrayOES(array);
 }
 
+GLvoid StubGLBlendBarrier() {
+  glBlendBarrierKHR();
+}
+
 GLvoid StubGLBlendColor(GLclampf red, GLclampf green, GLclampf blue,
                         GLclampf alpha) {
   glBlendColor(red, green, blue, alpha);
@@ -673,6 +677,7 @@ GrGLInterface* CreateInProcessSkiaGLBinding() {
   functions->fBindFragDataLocation = StubGLBindFragDataLocation;
   functions->fBindTexture = StubGLBindTexture;
   functions->fBindVertexArray = StubGLBindVertexArray;
+  functions->fBlendBarrier = StubGLBlendBarrier;
   functions->fBlendColor = StubGLBlendColor;
   functions->fBlendEquation = StubGLBlendEquation;
   functions->fBlendFunc = StubGLBlendFunc;