Support offscreen contexts which own their backing surface

third_party/WebKit/Source/modules/webgl/WebGLRenderingContextBase.cpp

 /*
  * Copyright (C) 2009 Apple Inc. All rights reserved.
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  * modification, are permitted provided that the following conditions
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  * 1. Redistributions of source code must retain the above copyright
  *    notice, this list of conditions and the following disclaimer.
  * 2. Redistributions in binary form must reproduce the above copyright
  *    notice, this list of conditions and the following disclaimer in the
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  *
  * THIS SOFTWARE IS PROVIDED BY APPLE COMPUTER, INC. ``AS IS'' AND ANY
  * EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
  * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL APPLE COMPUTER, INC. OR
  * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
  * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
  * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
  * PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY
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 #include "modules/webgl/WebGLRenderingContextBase.h"
 
+#include <memory>
 #include "bindings/core/v8/ExceptionMessages.h"
 #include "bindings/core/v8/ExceptionState.h"
 #include "bindings/core/v8/ScriptWrappableVisitor.h"
 #include "bindings/core/v8/V8BindingMacros.h"
 #include "bindings/modules/v8/HTMLCanvasElementOrOffscreenCanvas.h"
 #include "bindings/modules/v8/WebGLAny.h"
 #include "core/dom/DOMArrayBuffer.h"
 #include "core/dom/DOMTypedArray.h"
 #include "core/dom/FlexibleArrayBufferView.h"
 #include "core/dom/TaskRunnerHelper.h"
 #include "core/frame/ImageBitmap.h"
 #include "core/frame/LocalFrame.h"
 #include "core/frame/Settings.h"
 #include "core/html/HTMLCanvasElement.h"
 #include "core/html/HTMLImageElement.h"
 #include "core/html/HTMLVideoElement.h"
 #include "core/html/ImageData.h"
 #include "core/inspector/ConsoleMessage.h"
 #include "core/inspector/InspectorInstrumentation.h"
 #include "core/layout/LayoutBox.h"
 #include "core/loader/FrameLoader.h"
 #include "core/loader/FrameLoaderClient.h"
+#include "core/origin_trials/OriginTrials.h"
 #include "gpu/command_buffer/client/gles2_interface.h"
 #include "modules/webgl/ANGLEInstancedArrays.h"
 #include "modules/webgl/EXTBlendMinMax.h"
 #include "modules/webgl/EXTFragDepth.h"
 #include "modules/webgl/EXTShaderTextureLOD.h"
 #include "modules/webgl/EXTTextureFilterAnisotropic.h"
 #include "modules/webgl/GLStringQuery.h"
 #include "modules/webgl/OESElementIndexUint.h"
 #include "modules/webgl/OESStandardDerivatives.h"
 #include "modules/webgl/OESTextureFloat.h"
@@ skipping 35 matching lines @@
 #include "platform/graphics/gpu/AcceleratedImageBufferSurface.h"
 #include "platform/graphics/gpu/SharedGpuContext.h"
 #include "public/platform/Platform.h"
 #include "skia/ext/texture_handle.h"
 #include "wtf/CheckedNumeric.h"
 #include "wtf/Functional.h"
 #include "wtf/PtrUtil.h"
 #include "wtf/text/StringBuilder.h"
 #include "wtf/text/StringUTF8Adaptor.h"
 #include "wtf/typed_arrays/ArrayBufferContents.h"
-#include <memory>
 
 namespace blink {
 
 namespace {
 
 const double secondsBetweenRestoreAttempts = 1.0;
 const int maxGLErrorsAllowedToConsole = 256;
 const unsigned maxGLActiveContexts = 16;
 const unsigned maxGLActiveContextsOnWorker = 4;
 
@@ skipping 501 matching lines @@
     ScriptState* scriptState,
     const CanvasContextCreationAttributes& attributes,
     unsigned webGLVersion) {
   // Exactly one of these must be provided.
   DCHECK_EQ(!canvas, !!scriptState);
   // The canvas is only given on the main thread.
   DCHECK(!canvas || isMainThread());
 
   Platform::ContextAttributes contextAttributes =
       toPlatformContextAttributes(attributes, webGLVersion);
+
+  // If there's a possibility this context may be used with WebVR make sure it
+  // is created with an offscreen surface that can be swapped out for a
+  // VR-specific surface if needed. We can only check the origin trial
+  // if called with a scriptState, not for a canvas.

[amp, 2017/02/15 20:04:22]

Comment seems out of sync with code which does check the canvas for an origin
trial.

[klausw, 2017/02/15 20:21:15]

Done.

+  //
+  // At this time, treat this as an experimental rendering optimization
+  // that needs a separate opt-in. See crbug.com/691102 for details.
+  if (RuntimeEnabledFeatures::webVRExperimentalRenderingEnabled()) {
+    if (RuntimeEnabledFeatures::webVREnabled() ||
+        OriginTrials::webVREnabled(
+            canvas ? canvas->document().getExecutionContext()
+                   : scriptState->getExecutionContext())) {
+      DVLOG(1) << "Requesting supportOwnOffscreenSurface";
+      contextAttributes.supportOwnOffscreenSurface = true;
+    }
+  }
+
   Platform::GraphicsInfo glInfo;
   std::unique_ptr<WebGraphicsContext3DProvider> contextProvider;
   const auto& url = canvas ? canvas->document().topDocument().url()
                            : scriptState->getExecutionContext()->url();
   if (isMainThread()) {
     contextProvider = WTF::wrapUnique(
         Platform::current()->createOffscreenGraphicsContext3DProvider(
             contextAttributes, url, 0, &glInfo));
   } else {
     contextProvider =
@@ skipping 7161 matching lines @@
 
 void WebGLRenderingContextBase::getHTMLOrOffscreenCanvas(
     HTMLCanvasElementOrOffscreenCanvas& result) const {
   if (canvas())
     result.setHTMLCanvasElement(canvas());
   else
     result.setOffscreenCanvas(offscreenCanvas());
 }
 
 }  // namespace blink