Add force_compositing_mode support in gpu blacklist.

content/browser/gpu/gpu_util_unittest.cc

Index: content/browser/gpu/gpu_util_unittest.cc
===================================================================
--- content/browser/gpu/gpu_util_unittest.cc	(revision 176935)
+++ content/browser/gpu/gpu_util_unittest.cc	(working copy)
@@ -29,6 +29,8 @@
             GPU_FEATURE_TYPE_ACCELERATED_VIDEO);
   EXPECT_EQ(StringToGpuFeatureType("panel_fitting"),
             GPU_FEATURE_TYPE_PANEL_FITTING);
+  EXPECT_EQ(StringToGpuFeatureType("force_compositing_mode"),
+            GPU_FEATURE_TYPE_FORCE_COMPOSITING_MODE);
   EXPECT_EQ(StringToGpuFeatureType("all"), GPU_FEATURE_TYPE_ALL);
   EXPECT_EQ(StringToGpuFeatureType("xxx"), GPU_FEATURE_TYPE_UNKNOWN);
 }
@@ -66,6 +68,9 @@
       GpuFeatureTypeToString(GPU_FEATURE_TYPE_PANEL_FITTING).c_str(),
       "panel_fitting");
   EXPECT_STREQ(
+      GpuFeatureTypeToString(GPU_FEATURE_TYPE_FORCE_COMPOSITING_MODE).c_str(),
+      "force_compositing_mode");
+  EXPECT_STREQ(
       GpuFeatureTypeToString(GPU_FEATURE_TYPE_ALL).c_str(), "all");
   EXPECT_STREQ(GpuFeatureTypeToString(
       GPU_FEATURE_TYPE_UNKNOWN).c_str(), "unknown");