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

Source/core/html/canvas/WebGLRenderingContext.cpp

Index: Source/core/html/canvas/WebGLRenderingContext.cpp
diff --git a/Source/core/html/canvas/WebGLRenderingContext.cpp b/Source/core/html/canvas/WebGLRenderingContext.cpp
index 3f8e375d3e7e675fdaae90f88bce60d3dcb53f31..d8085b7596d12d4ccef82b2d681e457b9bdd3335 100644
--- a/Source/core/html/canvas/WebGLRenderingContext.cpp
+++ b/Source/core/html/canvas/WebGLRenderingContext.cpp
@@ -61,6 +61,8 @@
 
 namespace blink {
 
+static bool shouldFailContextCreationForTesting = false;
+
 PassOwnPtrWillBeRawPtr<WebGLRenderingContext> WebGLRenderingContext::create(HTMLCanvasElement* canvas, WebGLContextAttributes* attrs)
 {
     Document& document = canvas->document();
@@ -87,7 +89,7 @@ PassOwnPtrWillBeRawPtr<WebGLRenderingContext> WebGLRenderingContext::create(HTML
     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 = ");
@@ -96,6 +98,7 @@ PassOwnPtrWillBeRawPtr<WebGLRenderingContext> WebGLRenderingContext::create(HTML
         statusMessage.append(glInfo.driverVersion);
         statusMessage.append(".");
         canvas->dispatchEvent(WebGLContextEvent::create(EventTypeNames::webglcontextcreationerror, false, true, statusMessage));
+        shouldFailContextCreationForTesting = false;
         return nullptr;
     }
 
@@ -182,4 +185,9 @@ void WebGLRenderingContext::trace(Visitor* visitor)
     WebGLRenderingContextBase::trace(visitor);
 }
 
+void WebGLRenderingContext::forceNextWebGLContextCreationToFail()
+{
+    shouldFailContextCreationForTesting = true;
+}
+
 } // namespace blink