external/webp: enable WEBP_USE_THREAD

this serializes dsp function pointer initialization avoiding the
potential for multiple initialization or code reordering in the
non-threaded case. if the latter were to occur there would be a race
condition where the pointers had the potential to be uninitialized,
resulting in a crash.

Test: aosp_arm-eng aosp_arm64-eng aosp_x86-eng aosp_x86_64-eng
      aosp_crosshatch-userdebug build

Bug: https://crbug.com/webp/419
Bug: b/139274551
Change-Id: Iaecdf4718820d304d216fc7583ef2b0130a64e9a

1 files changed, 2 insertions, 0 deletions

diff --git a/Android.bp b/Android.bp
index ec57ba74..d7e0eb04 100644
--- a/Android.bp
+++ b/Android.bp
@@ -109,6 +109,7 @@ cc_library_static {
         "-O2",
         "-DANDROID",
         "-DWEBP_SWAP_16BIT_CSP",
+        "-DWEBP_USE_THREAD",
         "-Wall",
         "-Werror",
     ],
@@ -205,6 +206,7 @@ cc_library_static {
         "-O2",
         "-DANDROID",
         "-DWEBP_SWAP_16BIT_CSP",
+        "-DWEBP_USE_THREAD",
         "-Wall",
         "-Werror",
     ],