Fixing Canvas2DLayerBridge to handle lost graphics contexts

LayoutTests/virtual/gpu/fast/canvas/canvas-lost-gpu-context-expected.txt

Index: LayoutTests/virtual/gpu/fast/canvas/canvas-lost-gpu-context-expected.txt
diff --git a/LayoutTests/fast/canvas/canvas-drawImage-incomplete-expected.txt b/LayoutTests/virtual/gpu/fast/canvas/canvas-lost-gpu-context-expected.txt
similarity index 56%
copy from LayoutTests/fast/canvas/canvas-drawImage-incomplete-expected.txt
copy to LayoutTests/virtual/gpu/fast/canvas/canvas-lost-gpu-context-expected.txt
index e74bab16998300d710fdcfdd3334a55eefefa83a..34fb462c616aee7b89658ddeda7b53932dcc42a5 100644
--- a/LayoutTests/fast/canvas/canvas-drawImage-incomplete-expected.txt
+++ b/LayoutTests/virtual/gpu/fast/canvas/canvas-lost-gpu-context-expected.txt
@@ -1,19 +1,18 @@
-Test that drawImage() does nothing with an incomplete image or video
+Test the behavior of canvas recovery after a gpu context loss
 
 On success, you will see a series of "PASS" messages, followed by "TEST COMPLETE".
 
 
-PASS ctx.drawImage(img, 0, 0) is undefined
 PASS imgdata[0] is 255
 PASS imgdata[1] is 0
 PASS imgdata[2] is 0
 PASS imgdata[3] is 255
-PASS ctx.drawImage(video, 0, 0) is undefined
-PASS imgdata[0] is 255
+PASS imgdata[0] is 0
 PASS imgdata[1] is 0
 PASS imgdata[2] is 0
-PASS imgdata[3] is 255
+PASS imgdata[3] is 0
 PASS successfullyParsed is true
 
 TEST COMPLETE
+PASS Graphics context recovered.