Disable Canvas2DAllowed for OS_LINUX, it times out on Linux debug shared build bot.

chrome/test/gpu/gpu_feature_browsertest.cc

Index: chrome/test/gpu/gpu_feature_browsertest.cc
diff --git a/chrome/test/gpu/gpu_feature_browsertest.cc b/chrome/test/gpu/gpu_feature_browsertest.cc
index 4379c93a4393430633cd10af0f488251910c5e8b..a5559b86bba5b9015626104e56420a4aa2c24689 100644
--- a/chrome/test/gpu/gpu_feature_browsertest.cc
+++ b/chrome/test/gpu/gpu_feature_browsertest.cc
@@ -157,6 +157,10 @@ IN_PROC_BROWSER_TEST_F(GpuFeatureTest, WebGLBlocked) {
   RunTest(url, EXPECT_NO_GPU_PROCESS);
 }
 
+#if defined(OS_LINUX)
+// http://crbug.com/104142
+#define Canvas2DAllowed DISABLED_Canvas2DAllowed
+#endif
 IN_PROC_BROWSER_TEST_F(GpuFeatureTest, Canvas2DAllowed) {
   GpuFeatureFlags flags = GpuDataManager::GetInstance()->GetGpuFeatureFlags();
   EXPECT_EQ(flags.flags(), 0u);