Update from https://crrev.com/320931

gpu/command_buffer/client/BUILD.gn

Index: gpu/command_buffer/client/BUILD.gn
diff --git a/gpu/command_buffer/client/BUILD.gn b/gpu/command_buffer/client/BUILD.gn
index 23d5a8c14cc49812bd53422651e115c4d65f906e..d86edd4a1e3c880b9d657eb591eb7fade3f1dbe0 100644
--- a/gpu/command_buffer/client/BUILD.gn
+++ b/gpu/command_buffer/client/BUILD.gn
@@ -17,10 +17,11 @@ source_set("client") {
     "transfer_buffer.h",
   ]
 
-  defines = [ "GPU_IMPLEMENTATION" ]
-
-  # TODO(jschuh): crbug.com/167187 fix size_t to int truncations.
-  configs += [ "//build/config/compiler:no_size_t_to_int_warning" ]
+  configs += [
+    # TODO(jschuh): crbug.com/167187 fix size_t to int truncations.
+    "//build/config/compiler:no_size_t_to_int_warning",
+    "//gpu:gpu_implementation",
+  ]
 
   all_dependent_configs = [ "//third_party/khronos:khronos_headers" ]
 
@@ -52,10 +53,11 @@ source_set("gles2_cmd_helper_sources") {
     "gles2_cmd_helper_autogen.h",
   ]
 
-  defines = [ "GPU_IMPLEMENTATION" ]
-
-  # TODO(jschuh): crbug.com/167187 fix size_t to int truncations.
-  configs += [ "//build/config/compiler:no_size_t_to_int_warning" ]
+  configs += [
+    # TODO(jschuh): crbug.com/167187 fix size_t to int truncations.
+    "//build/config/compiler:no_size_t_to_int_warning",
+    "//gpu:gpu_implementation",
+  ]
 
   deps = [
     ":client",
@@ -116,6 +118,7 @@ source_set("gpu_memory_buffer_manager") {
     "gpu_memory_buffer_manager.cc",
     "gpu_memory_buffer_manager.h",
   ]
+  configs += [ "//gpu:gpu_implementation" ]
   deps = [
     "//ui/gfx",
   ]