Enable creation of offscreen contexts which own their backing surface.

ui/gl/init/gl_factory_android.cc

Index: ui/gl/init/gl_factory_android.cc
diff --git a/ui/gl/init/gl_factory_android.cc b/ui/gl/init/gl_factory_android.cc
index dbab9b003175e488e2714f66cb86b2fc041049bc..fc32a4fabc723d431ef017e328edc83b2ec144e4 100644
--- a/ui/gl/init/gl_factory_android.cc
+++ b/ui/gl/init/gl_factory_android.cc
@@ -133,19 +133,28 @@ scoped_refptr<GLSurface> CreateViewGLSurface(gfx::AcceleratedWidget window) {
 
 scoped_refptr<GLSurface> CreateOffscreenGLSurface(const gfx::Size& size) {
   TRACE_EVENT0("gpu", "gl::init::CreateOffscreenGLSurface");
+  scoped_refptr<GLSurface> surface =
+      CreateUninitializedOffscreenGLSurface(size);
+  if (surface && GetGLImplementation() != kGLImplementationMockGL)

[piman, 2016/11/16 00:44:03]

Here and other places: no need to check against kGLImplementationMockGL - the
reason we didn't call InitializeGLSurface on GLSurfaceStub is not so much that
it's wrong, but that it's a noop. But it would simplify to always call
Initialize on it.

[klausw, 2017/01/05 02:17:43]

Moot, no longer applicable in the new refactor.

+    InitializeGLSurface(surface);
+  return surface;
+}
+
+scoped_refptr<GLSurface> CreateUninitializedOffscreenGLSurface(
+    const gfx::Size& size) {
+  TRACE_EVENT0("gpu", "gl::init::CreateUninitializedOffscreenGLSurface");
   CHECK_NE(kGLImplementationNone, GetGLImplementation());
   switch (GetGLImplementation()) {
     case kGLImplementationOSMesaGL: {
-      return InitializeGLSurface(
-          new GLSurfaceOSMesa(GLSurface::SURFACE_OSMESA_BGRA, size));
+      return new GLSurfaceOSMesa(GLSurface::SURFACE_OSMESA_BGRA, size);
     }
     case kGLImplementationEGLGLES2: {
       scoped_refptr<GLSurface> surface;
       if (GLSurfaceEGL::IsEGLSurfacelessContextSupported() &&
           (size.width() == 0 && size.height() == 0)) {
-        return InitializeGLSurface(new SurfacelessEGL(size));
+        return new SurfacelessEGL(size);
       } else {
-        return InitializeGLSurface(new PbufferGLSurfaceEGL(size));
+        return new PbufferGLSurfaceEGL(size);
       }
     }
     case kGLImplementationMockGL: