Index: third_party/WebKit/Source/BUILD.gn |
diff --git a/third_party/WebKit/Source/BUILD.gn b/third_party/WebKit/Source/BUILD.gn |
index cfc9a242330bc1109f3126987b46506b74383119..b07ff56906d9972237917dba720722cfa10a0221 100644 |
--- a/third_party/WebKit/Source/BUILD.gn |
+++ b/third_party/WebKit/Source/BUILD.gn |
@@ -41,6 +41,44 @@ config("inside_blink") { |
] |
} |
+# blink_pch -------------------------------------------------------------------- |
+ |
+# Precompiled headers can save a lot of time compiling since Blink has |
+# a lot of source in header files. |
+ |
+import("//build/config/pch.gni") |
+ |
+config("blink_pch") { |
+ if (!disable_precompiled_headers) { |
+ if (is_win) { |
+ # This is a string rather than a file GN knows about. It has to match |
+ # exactly what's in the /FI flag below, and what might appear in the |
+ # source code in quotes for an #include directive. |
+ precompiled_header = rebase_path("build/win/Precompile.h", root_build_dir) |
+ |
+ # This is a file that GN will compile with the above header. It will be |
+ # implicitly added to the sources (potentially multiple times, with one |
+ # variant for each language used in the target). |
+ precompiled_source = |
+ "//third_party/WebKit/Source/build/win/Precompile.cpp" |
+ |
+ # Force include the header. |
+ cflags = [ "/FI$precompiled_header" ] |
+ |
+ # Disable warning for "this file was empty after preprocessing". This |
+ # error is generated only in C mode for ANSI compatibility. It conflicts |
+ # with precompiled headers since the source file that's "compiled" for |
+ # making the precompiled header is empty. |
+ # |
+ # This error doesn't happen every time. In VS2013, it seems if the .pch |
+ # file doesn't exist, no error will be generated (probably MS tested this |
+ # case but forgot the other one?). To reproduce this error, do a build, |
+ # then delete the precompile.c.obj file, then build again. |
+ cflags_c = [ "/wd4206" ] |
+ } |
+ } |
+} |
+ |
# config ----------------------------------------------------------------------- |
config("config") { |