Use Stub CDM for building libwidevinecdmadapter.so

third_party/widevine/cdm/BUILD.gn

Index: third_party/widevine/cdm/BUILD.gn
diff --git a/third_party/widevine/cdm/BUILD.gn b/third_party/widevine/cdm/BUILD.gn
index dda97991ca4b0c533ae7a5830d9e9d9195a86811..b66c652c0aebd8be609ce55e4964f50175098437 100644
--- a/third_party/widevine/cdm/BUILD.gn
+++ b/third_party/widevine/cdm/BUILD.gn
@@ -18,6 +18,16 @@ if (widevine_arch == "x86") {
 widevine_cdm_binary_files = []
 widevine_cdm_manifest_file = []
 
+# Due to crbug.com/707488, in linux and chromeos chrome, we temporarily use
+# stub cdm for building cdm adapter and copy the real cdm after that.
+# The stub libwidevinecdm.so is in the sub-directory "./stub_cdm" to avoid
+# GN's complaint about generating the same output in two targets.
+# TODO(hmchen): Revert this change after crbug.com/707488 fixed.
+use_stub_cdm_for_chrome = false
+if (is_chrome_branded && is_linux) {
+  use_stub_cdm_for_chrome = true
+}
+
 if (is_android) {
   # Always available on Android regardless of branding.
   widevine_cdm_version_h_file = "android/widevine_cdm_version.h"
@@ -82,7 +92,40 @@ source_set("headers") {
   ]
 }
 
-if (widevine_cdm_binary_files != []) {
+if (use_stub_cdm_for_chrome) {
+  widevine_cdm_binary_files = []
+  copy("copy_widevinecdm") {
+    if (is_chromeos) {
+      widevine_cdm = [ "chromeos/$widevine_arch/libwidevinecdm.so" ]
+    } else if (is_linux) {
+      widevine_cdm = [ "linux/$widevine_arch/libwidevinecdm.so" ]
+    }
+    sources = widevine_cdm
+    outputs = [
+      "$root_out_dir/$widevine_cdm_path/{{source_file_part}}",
+    ]
+  }
+
+  shared_library("widevinecdm") {
+    output_dir = "$root_out_dir/$widevine_cdm_path/stub_cdm"
+    sources = [
+      "//media/cdm/stub/stub_cdm.cc",
+      "//media/cdm/stub/stub_cdm.h",
+    ]
+
+    defines = [ "CDM_IMPLEMENTATION" ]
+
+    deps = [
+      ":version_h",
+      ":copy_widevinecdm",
+      "//base",
+      "//build/config/sanitizers:deps",
+    ]
+
+    public_deps = [ ":copy_widevinecdm" ]
+    cflags = [ "-fvisibility=hidden" ]
+  }
+} else if (widevine_cdm_binary_files != []) {
   copy("widevinecdm") {
     sources = widevine_cdm_binary_files
     outputs = [
@@ -165,7 +208,7 @@ if ((is_chrome_branded || enable_widevine) && enable_pepper_cdms) {
       ":widevinecdm",
     ]
 
-    if (is_linux) {
+    if (is_linux && !use_stub_cdm_for_chrome) {
       ldflags =
           [ rebase_path("$root_out_dir/$widevine_cdm_path/libwidevinecdm.so",
                         root_build_dir) ]