Implement offscreenCanvas.getContext('webgl') on a worker thread

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

Index: third_party/WebKit/Source/modules/webgl/WebGLRenderingContextBase.cpp
diff --git a/third_party/WebKit/Source/modules/webgl/WebGLRenderingContextBase.cpp b/third_party/WebKit/Source/modules/webgl/WebGLRenderingContextBase.cpp
index 26f07ba35e335d19dcc1d2cb2c91b643b4066e83..e8e2c5e90a02d806603bcafe9fb1634de3cd467c 100644
--- a/third_party/WebKit/Source/modules/webgl/WebGLRenderingContextBase.cpp
+++ b/third_party/WebKit/Source/modules/webgl/WebGLRenderingContextBase.cpp
@@ -66,7 +66,6 @@
 #include "modules/webgl/WebGLCompressedTexturePVRTC.h"
 #include "modules/webgl/WebGLCompressedTextureS3TC.h"
 #include "modules/webgl/WebGLContextAttributeHelpers.h"
-#include "modules/webgl/WebGLContextAttributes.h"
 #include "modules/webgl/WebGLContextEvent.h"
 #include "modules/webgl/WebGLContextGroup.h"
 #include "modules/webgl/WebGLDebugRendererInfo.h"
@@ -79,19 +78,18 @@
 #include "modules/webgl/WebGLRenderbuffer.h"
 #include "modules/webgl/WebGLShader.h"
 #include "modules/webgl/WebGLShaderPrecisionFormat.h"
-#include "modules/webgl/WebGLTexture.h"
 #include "modules/webgl/WebGLUniformLocation.h"
 #include "modules/webgl/WebGLVertexArrayObject.h"
 #include "modules/webgl/WebGLVertexArrayObjectOES.h"
 #include "platform/CheckedInt.h"
 #include "platform/RuntimeEnabledFeatures.h"
+#include "platform/ThreadSafeFunctional.h"
+#include "platform/WaitableEvent.h"
 #include "platform/geometry/IntSize.h"
 #include "platform/graphics/GraphicsContext.h"
 #include "platform/graphics/UnacceleratedImageBufferSurface.h"
 #include "platform/graphics/gpu/AcceleratedImageBufferSurface.h"
-#include "platform/graphics/gpu/DrawingBuffer.h"
 #include "public/platform/Platform.h"
-#include "public/platform/WebGraphicsContext3DProvider.h"
 #include "public/platform/functional/WebFunction.h"
 #include "wtf/Functional.h"
 #include "wtf/PassOwnPtr.h"
@@ -502,7 +500,17 @@ static String extractWebGLContextCreationError(const Platform::GraphicsInfo& inf
     return statusMessage;
 }
 
-static PassOwnPtr<WebGraphicsContext3DProvider> createWebGraphicsContext3DProviderInternal(HTMLCanvasElement* canvas, ScriptState* scriptState, WebGLContextAttributes attributes, unsigned webGLVersion)
+void WebGLRenderingContextBase::createWebGraphicsContext3DProviderMainThread(WebGLRenderingContextBase::createWebGraphicsContext3DProviderUtils* createUtils, WaitableEvent* waitableEvent)

[Justin Novosad, 2016/05/04 18:34:03]

"OnMainThread"

+{
+    ASSERT(isMainThread());
+    Platform::GraphicsInfo glInfo = createUtils->glInfo();
+    OwnPtr<WebGraphicsContext3DProvider> provider = adoptPtr(Platform::current()->createOffscreenGraphicsContext3DProvider(
+        createUtils->contextAttributes(), createUtils->scriptState()->getExecutionContext()->url(), 0, &glInfo));
+    createUtils->setContextProvider(provider.release());
+    waitableEvent->signal();
+}
+
+PassOwnPtr<WebGraphicsContext3DProvider> WebGLRenderingContextBase::createWebGraphicsContext3DProviderInternal(HTMLCanvasElement* canvas, ScriptState* scriptState, WebGLContextAttributes attributes, unsigned webGLVersion)
 {
     Platform::ContextAttributes contextAttributes = toPlatformContextAttributes(attributes, webGLVersion);
     Platform::GraphicsInfo glInfo;
@@ -511,8 +519,18 @@ static PassOwnPtr<WebGraphicsContext3DProvider> createWebGraphicsContext3DProvid
         contextProvider = adoptPtr(Platform::current()->createOffscreenGraphicsContext3DProvider(
             contextAttributes, canvas->document().topDocument().url(), 0, &glInfo));
     } else {
-        contextProvider = adoptPtr(Platform::current()->createOffscreenGraphicsContext3DProvider(
-            contextAttributes, scriptState->getExecutionContext()->url(), 0, &glInfo));
+        if (isMainThread()) {
+            contextProvider = adoptPtr(Platform::current()->createOffscreenGraphicsContext3DProvider(
+                contextAttributes, scriptState->getExecutionContext()->url(), 0, &glInfo));
+        } else {
+            WaitableEvent waitableEvent;
+            WebTaskRunner* taskRunner = Platform::current()->mainThread()->getWebTaskRunner();
+            OwnPtr<WebGLRenderingContextBase::createWebGraphicsContext3DProviderUtils> createUtils = adoptPtr(new WebGLRenderingContextBase::createWebGraphicsContext3DProviderUtils(contextAttributes, glInfo, scriptState));
+            taskRunner->postTask(BLINK_FROM_HERE, threadSafeBind(&createWebGraphicsContext3DProviderMainThread, AllowCrossThreadAccess(createUtils.get()), AllowCrossThreadAccess(&waitableEvent)));
+            waitableEvent.wait();
+            contextProvider = createUtils->releaseContextProvider();
+            contextProvider->DetachFromThread();
+        }
     }
     if (!contextProvider || shouldFailContextCreationForTesting) {
         shouldFailContextCreationForTesting = false;
@@ -526,7 +544,6 @@ static PassOwnPtr<WebGraphicsContext3DProvider> createWebGraphicsContext3DProvid
             canvas->dispatchEvent(WebGLContextEvent::create(EventTypeNames::webglcontextcreationerror, false, true, "OES_packed_depth_stencil support is required."));
         return nullptr;
     }
-
     return contextProvider.release();
 }