[WebGL-blink] Add test function to force fail the webgl-context

Source/core/html/canvas/WebGLRenderingContext.cpp

 /*
  * Copyright (C) 2009 Apple 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:
  * 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
@@ skipping 43 matching lines @@
 #include "core/loader/FrameLoader.h"
 #include "core/loader/FrameLoaderClient.h"
 #include "core/frame/Settings.h"
 #include "core/rendering/RenderBox.h"
 #include "platform/CheckedInt.h"
 #include "platform/graphics/gpu/DrawingBuffer.h"
 #include "public/platform/Platform.h"
 
 namespace blink {
 
+static bool shouldFailContextCreationForTesting = false;
+
 PassOwnPtrWillBeRawPtr<WebGLRenderingContext> WebGLRenderingContext::create(HTMLCanvasElement* canvas, WebGLContextAttributes* attrs)
 {
     Document& document = canvas->document();
     LocalFrame* frame = document.frame();
     if (!frame) {
         canvas->dispatchEvent(WebGLContextEvent::create(EventTypeNames::webglcontextcreationerror, false, true, "Web page was not allowed to create a WebGL context."));
         return nullptr;
     }
     Settings* settings = frame->settings();
 
     // The FrameLoaderClient might block creation of a new WebGL context despite the page settings; in
     // particular, if WebGL contexts were lost one or more times via the GL_ARB_robustness extension.
     if (!frame->loader().client()->allowWebGL(settings && settings->webGLEnabled())) {
         canvas->dispatchEvent(WebGLContextEvent::create(EventTypeNames::webglcontextcreationerror, false, true, "Web page was not allowed to create a WebGL context."));
         return nullptr;
     }
 
     // The only situation that attrs is null is through Document::getCSSCanvasContext().
     RefPtrWillBeRawPtr<WebGLContextAttributes> defaultAttrs = nullptr;
     if (!attrs) {
         defaultAttrs = WebGLContextAttributes::create();
         attrs = defaultAttrs.get();
     }
     blink::WebGraphicsContext3D::Attributes attributes = attrs->attributes(document.topDocument().url().string(), settings, 1);
     blink::WebGLInfo glInfo;
     OwnPtr<blink::WebGraphicsContext3D> context = adoptPtr(blink::Platform::current()->createOffscreenGraphicsContext3D(attributes, 0, &glInfo));
-    if (!context) {
+    if (!context || shouldFailContextCreationForTesting) {
         String statusMessage("Could not create a WebGL context for VendorInfo = ");
         statusMessage.append(glInfo.vendorInfo);
         statusMessage.append(", RendererInfo = ");
         statusMessage.append(glInfo.rendererInfo);
         statusMessage.append(", DriverInfo = ");
         statusMessage.append(glInfo.driverVersion);
         statusMessage.append(".");
         canvas->dispatchEvent(WebGLContextEvent::create(EventTypeNames::webglcontextcreationerror, false, true, statusMessage));
+        shouldFailContextCreationForTesting = false;

[Ken Russell (switch to Gerrit), 2014/11/12 21:26:02]

This should be moved up to the beginning of the block, before the dispatchEvent
call. Otherwise if the event listener tries to create a WebGL context it'll fail
too.

[sivag, 2014/11/13 03:40:31]

Done.

         return nullptr;
     }
 
     OwnPtr<Extensions3DUtil> extensionsUtil = Extensions3DUtil::create(context.get());
     if (!extensionsUtil)
         return nullptr;
     if (extensionsUtil->supportsExtension("GL_EXT_debug_marker"))
         context->pushGroupMarkerEXT("WebGLRenderingContext");
 
     OwnPtrWillBeRawPtr<WebGLRenderingContext> renderingContext = adoptPtrWillBeNoop(new WebGLRenderingContext(canvas, context.release(), attrs));
@@ skipping 66 matching lines @@
     visitor->trace(m_webglDebugShaders);
     visitor->trace(m_webglDrawBuffers);
     visitor->trace(m_webglCompressedTextureATC);
     visitor->trace(m_webglCompressedTextureETC1);
     visitor->trace(m_webglCompressedTexturePVRTC);
     visitor->trace(m_webglCompressedTextureS3TC);
     visitor->trace(m_webglDepthTexture);
     WebGLRenderingContextBase::trace(visitor);
 }
 
+void WebGLRenderingContext::forceNextWebGLContextCreationToFail()
+{
+    shouldFailContextCreationForTesting = true;
+}
+
 } // namespace blink