gpu: Remove WebGraphicsContext3D::makeContextCurrent() in Blink

public/platform/WebGraphicsContext3D.h

 /*
  * Copyright (C) 2012 Google Inc. All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions are
  * met:
  *
  *     * Redistributions of source code must retain the above copyright
  * notice, this list of conditions and the following disclaimer.
  *     * Redistributions in binary form must reproduce the above
@@ skipping 128 matching lines @@
 
     protected:
         virtual ~WebGraphicsSwapBuffersCompleteCallbackCHROMIUM() { }
     };
 
     // This destructor needs to be public so that using classes can destroy instances if initialization fails.
     virtual ~WebGraphicsContext3D() { }
 
     // Makes the OpenGL context current on the current thread. Returns true on
     // success.
-    virtual bool makeContextCurrent() = 0;
+    // TODO(dshwang): remove it. crbug.com/404121
+    virtual bool makeContextCurrent() { return true; }
 
     // Each flush or finish is assigned an unique ID. The larger
     // the ID number, the more recently the context has been flushed.
     virtual uint32_t lastFlushID() { return 0; }
 
     // Resizes the region into which this WebGraphicsContext3D is drawing.
     virtual void reshapeWithScaleFactor(int width, int height, float scaleFactor) { }
 
     // GL_CHROMIUM_setVisibility - Changes the visibility of the backbuffer
     virtual void setVisibilityCHROMIUM(bool visible) = 0;
@@ skipping 313 matching lines @@
     virtual void vertexAttribDivisorANGLE(WGC3Duint index, WGC3Duint divisor) { }
 
     // GL_EXT_multisampled_render_to_texture
     virtual void framebufferTexture2DMultisampleEXT(WGC3Denum target, WGC3Denum attachment, WGC3Denum textarget, WebGLId texture, WGC3Dint level, WGC3Dsizei samples) { }
     virtual void renderbufferStorageMultisampleEXT(WGC3Denum target, WGC3Dsizei samples, WGC3Denum internalformat, WGC3Dsizei width, WGC3Dsizei height) { };
 };
 
 } // namespace blink
 
 #endif