Fixed layout test fast/canvas/canvas-bg.html to work with accelerated canvas

This patch removes the semi-transparent color used int the test, which
was irrelevant to the feature being testes and was causing the test
to fail due to rounding errors in compositing.

BUG=368008

Review URL: https://codereview.chromium.org/302083006

git-svn-id: svn://svn.chromium.org/blink/trunk@175164 bbb929c8-8fbe-4397-9dbb-9b2b20218538

third_party/WebKit/LayoutTests/TestExpectations

@@ -1027,7 +1027,6 @@ crbug.com/308992 svg/as-object/sizing/svg-in-object-placeholder-height-auto.html
 crbug.com/308992 svg/as-object/sizing/svg-in-object-placeholder-height-fixed.html [ Pass Timeout ]
 crbug.com/308992 svg/as-object/sizing/svg-in-object-placeholder-height-percentage.html [ Pass Timeout ]
 
-crbug.com/368008 virtual/gpu/fast/canvas/canvas-bg.html [ Skip ]
 crbug.com/368531 virtual/gpu/fast/canvas/canvas-path-addpath.html [ Failure Pass ]
 
 # Expectations changes due to switiching to In-renderer Shared Worker.

third_party/WebKit/LayoutTests/fast/canvas/canvas-bg-expected.html

@@ -10,7 +10,7 @@ function draw() {
  ctx.fillRect (10, 310, 55, 50);
  ctx.fillRect (310, 310, 55, 50);
 
- ctx.fillStyle = "rgba(0, 0, 200, 0.5)";
+ ctx.fillStyle = "rgb(0, 0, 200)";
  ctx.fillRect (30, 30, 55, 50);
  ctx.fillRect (330, 30, 55, 50);
  ctx.fillRect (30, 330, 55, 50);

third_party/WebKit/LayoutTests/fast/canvas/canvas-bg.html

@@ -11,7 +11,7 @@ function draw(w, h) {
  ctx.fillStyle = "rgb(200,0,0)";
  ctx.fillRect (10, 10, 55, 50);
 
- ctx.fillStyle = "rgba(0, 0, 200, 0.5)";
+ ctx.fillStyle = "rgb(0, 0, 200)";
  ctx.fillRect (30, 30, 55, 50);
 }
   </script>