gpu: Remove WebGraphicsContext3D::makeContextCurrent() in Blink

Source/platform/graphics/ImageBuffer.cpp

 /*
  * Copyright (c) 2008, Google Inc. All rights reserved.
  * Copyright (C) 2009 Dirk Schulze <krit@webkit.org>
  * Copyright (C) 2010 Torch Mobile (Beijing) Co. Ltd. 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
@@ skipping 162 matching lines @@
     if (!m_surface->isAccelerated() || !platformLayer() || !isSurfaceValid())
         return false;
 
     if (!Extensions3DUtil::canUseCopyTextureCHROMIUM(internalFormat, destType, level))
         return false;
 
     OwnPtr<WebGraphicsContext3DProvider> provider = adoptPtr(Platform::current()->createSharedOffscreenGraphicsContext3DProvider());
     if (!provider)
         return false;
     WebGraphicsContext3D* sharedContext = provider->context3d();
-    if (!sharedContext || !sharedContext->makeContextCurrent())
+    if (!sharedContext)
         return false;
 
     OwnPtr<WebExternalTextureMailbox> mailbox = adoptPtr(new WebExternalTextureMailbox);
 
     // Contexts may be in a different share group. We must transfer the texture through a mailbox first
     sharedContext->genMailboxCHROMIUM(mailbox->name);
     sharedContext->produceTextureDirectCHROMIUM(getBackingTexture(), GL_TEXTURE_2D, mailbox->name);
     sharedContext->flush();
 
     mailbox->syncPoint = sharedContext->insertSyncPoint();
 
-    if (!context->makeContextCurrent())
-        return false;
-
     context->waitSyncPoint(mailbox->syncPoint);
     Platform3DObject sourceTexture = context->createAndConsumeTextureCHROMIUM(GL_TEXTURE_2D, mailbox->name);
 
     // The canvas is stored in a premultiplied format, so unpremultiply if necessary.
     context->pixelStorei(GC3D_UNPACK_UNPREMULTIPLY_ALPHA_CHROMIUM, !premultiplyAlpha);
 
     // The canvas is stored in an inverted position, so the flip semantics are reversed.
     context->pixelStorei(GC3D_UNPACK_FLIP_Y_CHROMIUM, !flipY);
     context->copyTextureCHROMIUM(GL_TEXTURE_2D, sourceTexture, texture, level, internalFormat, destType);
 
@@ skipping 226 matching lines @@
     if (!encodeImage(imageData, mimeType, quality, &encodedImage))
         return "data:,";
 
     Vector<char> base64Data;
     base64Encode(encodedImage, base64Data);
 
     return "data:" + mimeType + ";base64," + base64Data;
 }
 
 } // namespace blink